diff --git a/README.md b/README.md
index b58fecc..131c001 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,7 @@ npm install --save-dev babel-plugin-css-modules-transform
     "plugins": [
         [
             "css-modules-transform", { 
+                "extensions": ['.css'], // which files to parse
                 "generateScopedName": "[name]__[local]___[hash:base64:5]", // in case you don't want to use a function
                 "generateScopedName": "./path/to/module-exporting-a-function.js", // in case you want to use a function
                 "generateScopedName": "npm-module-name",
diff --git a/src/index.js b/src/index.js
index 2752846..479c70f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -24,115 +24,183 @@ export default function transformCssModules({ types: t }) {
         return resolve(dir);
     }
 
+    /**
+     *
+     * @param {String} filepath     javascript file path
+     * @param {String} cssFile      requireed css file path
+     * @returns {Array} array of class names
+     */
+    function requireCssFile(filepath, cssFile) {
+        const from = resolveModulePath(filepath);
+        return require(resolve(from, cssFile));
+    }
+
     return {
         visitor: {
-            CallExpression(path, { file, opts }) {
-                const currentConfig = { ...defaultOptions, ...opts };
+            Program: {
+                enter(path, state) {
+                    state.$$css = {
+                        styles: new Map()
+                    };
+
+                    const { extensions = ['.css'] } = state.opts;
 
-                // check if there are simple requires and if they are functions
-                simpleRequires.forEach(key => {
-                    if (typeof currentConfig[key] !== 'string') {
-                        return;
+                    if (!Array.isArray(extensions)) {
+                        throw new Error('Extensions configurations has to be an array');
                     }
 
-                    const modulePath = resolve(process.cwd(), currentConfig[key]);
+                    state.$$css.extensions = new RegExp(`(${extensions.join('|').replace('.', '\\.')})$`, 'i');
 
-                    // this one can be require or string
-                    if (key === 'generateScopedName') {
-                        try {
-                            // if it is existing file, require it, otherwise use value
-                            currentConfig[key] = require(modulePath);
-                        } catch (e) {
-                            try {
-                                currentConfig[key] = require(currentConfig[key]);
-                            } catch (_e) {
-                                // do nothing, because it is not a valid path
-                            }
+                    // initialize css modules require hook
+                    const currentConfig = { ...defaultOptions, ...state.opts };
+
+                    const pushStylesCreator = (toWrap) => (css, filepath) => {
+                        if (!state.$$css.styles.has(filepath)) {
+                            state.$$css.styles.set(filepath, css);
                         }
 
-                        if (typeof currentConfig[key] !== 'function' && typeof currentConfig[key] !== 'string') {
-                            throw new Error(`Configuration '${key}' is not a string or function.`);
+                        if (typeof toWrap === 'function') {
+                            return toWrap(css, filepath);
                         }
+                    };
 
-                        return;
-                    }
+                    // check if there are simple requires and if they are functions
+                    simpleRequires.forEach(key => {
+                        if (typeof currentConfig[key] !== 'string') {
+                            return;
+                        }
 
-                    if (currentConfig.hasOwnProperty(key)) {
-                        try {
-                            currentConfig[key] = require(modulePath);
-                        } catch (e) {
+                        const modulePath = resolve(process.cwd(), currentConfig[key]);
+
+                        // this one can be require or string
+                        if (key === 'generateScopedName') {
                             try {
-                                currentConfig[key] = require(currentConfig[key]);
-                            } catch (_e) {
-                                // do nothing because it is not a valid path
+                                // if it is existing file, require it, otherwise use value
+                                currentConfig[key] = require(modulePath);
+                            } catch (e) {
+                                try {
+                                    currentConfig[key] = require(currentConfig[key]);
+                                } catch (_e) {
+                                    // do nothing, because it is not a valid path
+                                }
                             }
+
+                            if (typeof currentConfig[key] !== 'function' && typeof currentConfig[key] !== 'string') {
+                                throw new Error(`Configuration '${key}' is not a string or function.`);
+                            }
+
+                            return;
                         }
 
-                        if (typeof currentConfig[key] !== 'function') {
-                            throw new Error(`Module '${modulePath}' does not exist or is not a function.`);
+                        if (currentConfig.hasOwnProperty(key)) {
+                            try {
+                                currentConfig[key] = require(modulePath);
+                            } catch (e) {
+                                try {
+                                    currentConfig[key] = require(currentConfig[key]);
+                                } catch (_e) {
+                                    // do nothing because it is not a valid path
+                                }
+                            }
+
+                            if (typeof currentConfig[key] !== 'function') {
+                                throw new Error(`Module '${modulePath}' does not exist or is not a function.`);
+                            }
+
+                            // if processCss is name of configuration key, then wrap it to own function
+                            // otherwise it will be just defined
+                            if (key === 'processCss') {
+                                currentConfig[key] = pushStylesCreator(currentConfig[key]);
+                            }
                         }
-                    }
-                });
+                    });
 
-                complexRequires.forEach(key => {
-                    if (!currentConfig.hasOwnProperty(key)) {
-                        return;
+                    // if processCss is not defined, define it
+                    if (typeof currentConfig.processCss === 'undefined') {
+                        currentConfig.processCss = pushStylesCreator();
                     }
 
-                    if (!Array.isArray(currentConfig[key])) {
-                        throw new Error(`Configuration '${key}' has to be an array.`);
-                    }
+                    complexRequires.forEach(key => {
+                        if (!currentConfig.hasOwnProperty(key)) {
+                            return;
+                        }
+
+                        if (!Array.isArray(currentConfig[key])) {
+                            throw new Error(`Configuration '${key}' has to be an array.`);
+                        }
 
-                    currentConfig[key].forEach((plugin, index) => {
-                        // first try to load it using npm
-                        try {
-                            currentConfig[key][index] = require(plugin);
-                        } catch (e) {
+                        currentConfig[key].forEach((plugin, index) => {
+                            // first try to load it using npm
                             try {
-                                currentConfig[key][index] = require(resolve(process.cwd(), path));
-                            } catch (_e) {
-                                // do nothing
+                                currentConfig[key][index] = require(plugin);
+                            } catch (e) {
+                                try {
+                                    currentConfig[key][index] = require(resolve(process.cwd(), path));
+                                } catch (_e) {
+                                    // do nothing
+                                }
                             }
-                        }
 
-                        if (typeof currentConfig[key][index] !== 'function') {
-                            throw new Error(`Configuration '${key}' has to be valid path to a module at index ${index} or it does not export a function.`);
-                        }
+                            if (typeof currentConfig[key][index] !== 'function') {
+                                throw new Error(`Configuration '${key}' has to be valid path to a module at index ${index} or it does not export a function.`);
+                            }
 
-                        currentConfig[key][index] = currentConfig[key][index]();
+                            currentConfig[key][index] = currentConfig[key][index]();
+                        });
                     });
-                });
 
-                require('css-modules-require-hook')(currentConfig);
+                    require('css-modules-require-hook')(currentConfig);
+                },
+
+                /* eslint-disable no-unused-vars */
+                exit(path, state) {
+                    // todo extract to files / file (propably needs appending in case of single file because exit is called for each js file)
+                }
+            },
 
+            ImportDeclaration(path, { file, $$css: { extensions }}) {
+                // this method is called between enter and exit, so we can map css to our state
+                // it is then replaced with require call which will be handled in seconds pass by CallExpression
+                // CallExpression will then replace it or remove depending on parent node (if is Program or not)
+                const { value } = path.node.source;
+
+                // do nothing if not known extension
+                if (!extensions.exec(value)) {
+                    return;
+                }
+
+                requireCssFile(file.opts.filename, value);
+            },
+
+            CallExpression(path, { file, $$css: { extensions } }) {
                 const { callee: { name: calleeName }, arguments: args } = path.node;
 
                 if (calleeName !== 'require' || !args.length || !t.isStringLiteral(args[0])) {
                     return;
                 }
 
-                if (/\.css/i.test(args[0].value)) {
-                    const [ { value: cssPath }] = args;
-
-                    // if parent expression is variable declarator, replace right side with tokens
-                    if (!t.isVariableDeclarator(path.parent)) {
-                        throw new Error(
-                            `You can't import css file ${cssPath} to a module scope.`
-                        );
-                    }
+                // if we are not requiring css, ignore
+                if (!extensions.exec(args[0].value)) {
+                    return;
+                }
 
-                    const from = resolveModulePath(file.opts.filename);
-                    const tokens = require(resolve(from, cssPath));
+                // if parent expression is not a variable declarator, just remove require from file
+                // we just want to get generated css for our output
+                const tokens = requireCssFile(file.opts.filename, args[0].value);
 
+                // if parent expression is not a Program, replace expression with tokens
+                if (!t.isExpressionStatement(path.parent)) {
                     /* eslint-disable new-cap */
                     path.replaceWith(t.ObjectExpression(
-                            Object.keys(tokens).map(
-                                token => t.ObjectProperty(
+                        Object.keys(tokens).map(
+                            token => t.ObjectProperty(
                                 t.StringLiteral(token),
                                 t.StringLiteral(tokens[token])
                             )
                         )
                     ));
+                } else {
+                    path.remove();
                 }
             }
         }
diff --git a/test/index.spec.js b/test/index.spec.js
index 364bd92..9da6366 100644
--- a/test/index.spec.js
+++ b/test/index.spec.js
@@ -16,7 +16,7 @@ describe('babel-plugin-css-modules-transform', () => {
                 'transform-object-rest-spread',
                 'transform-es2015-spread',
                 'transform-export-extensions',
-                ['../src/index.js', configuration]
+                ['../../src/index.js', configuration]
             ]
         });
     }
@@ -25,14 +25,10 @@ describe('babel-plugin-css-modules-transform', () => {
         return readFileSync(resolve(__dirname, path), 'utf8');
     }
 
-    it('should throw if we are requiring css module to module scope', () => {
-        expect(() => transform('fixtures/global.require.js')).to.throw(
-            /^.+: You can't import css file .+ to a module scope\.$/
-        );
+    it('should not throw if we are requiring css module to module scope', () => {
+        expect(() => transform('fixtures/global.require.js')).to.not.throw();
 
-        expect(() => transform('fixtures/global.import.js')).to.throw(
-            /^.+: You can't import css file .+ to a module scope\.$/
-        );
+        expect(() => transform('fixtures/global.import.js')).to.not.throw();
     });
 
     it('should throw if generateScopeName is not exporting a function', () => {
@@ -114,7 +110,7 @@ describe('babel-plugin-css-modules-transform', () => {
                 'transform-object-rest-spread',
                 'transform-es2015-spread',
                 'transform-export-extensions',
-                ['../src/index.js', {}]
+                ['../../src/index.js', {}]
             ]
         });