diff --git a/demo/package.json b/demo/package.json
index deb75b0..be31c1a 100644
--- a/demo/package.json
+++ b/demo/package.json
@@ -5,6 +5,7 @@
   },
   "dependencies": {
     "babel-plugin-react-css-modules": "^2.1.3",
+    "classnames": "^2.2.6",
     "react": "^15.4.1",
     "react-dom": "^15.4.1",
     "webpack": "^2.2.0-rc.3"
diff --git a/demo/src/components/JSXExpressionStyleResolution.js b/demo/src/components/JSXExpressionStyleResolution.js
new file mode 100644
index 0000000..a70c9bc
--- /dev/null
+++ b/demo/src/components/JSXExpressionStyleResolution.js
@@ -0,0 +1,15 @@
+import React from 'react';
+import classnames from 'classnames';
+import './table.css';
+
+export default () => {
+  var cname = classnames({'row': true});
+
+  return <div className={classnames('table')}>
+    <div className={cname}>
+      <div styleName='cell'>A2</div>
+      <div styleName='cell'>B2</div>
+      <div styleName='cell'>C2</div>
+    </div>
+  </div>;
+};
diff --git a/demo/src/index.js b/demo/src/index.js
index ff0febf..aa82139 100644
--- a/demo/src/index.js
+++ b/demo/src/index.js
@@ -3,9 +3,11 @@ import ReactDom from 'react-dom';
 import AnonymouseStyleResolution from './components/AnonymouseStyleResolution';
 import NamedStyleResolution from './components/NamedStyleResolution';
 import RuntimeStyleResolution from './components/RuntimeStyleResolution';
+import JSXExpressionStyleResolution from './components/JSXExpressionStyleResolution';
 
 ReactDom.render(<div>
   <AnonymouseStyleResolution />
   <NamedStyleResolution />
+  <JSXExpressionStyleResolution />
   <RuntimeStyleResolution />
 </div>, document.getElementById('main'));
diff --git a/demo/webpack.config.js b/demo/webpack.config.js
index 4a63762..a3b23dc 100644
--- a/demo/webpack.config.js
+++ b/demo/webpack.config.js
@@ -23,7 +23,7 @@ module.exports = {
           plugins: [
             'transform-react-jsx',
             [
-              'react-css-modules',
+              require('../dist/index.js').default,
               {
                 context
               }
diff --git a/package.json b/package.json
index 32f4660..d1501a7 100644
--- a/package.json
+++ b/package.json
@@ -49,14 +49,15 @@
   "name": "babel-plugin-react-css-modules",
   "repository": {
     "type": "git",
-    "url": "https://github.com/gajus/babel-plugin-react-css-modules"
+    "url": "https://github.com/supriya-raj/babel-plugin-react-css-modules"
   },
   "scripts": {
     "build": "rm -fr ./dist && NODE_ENV=production babel ./src --out-dir ./dist --source-maps --copy-files && npm run build-helper",
     "build-helper": "mkdir -p ./dist/browser && NODE_ENV=production babel ./src/getClassName.js --out-file ./dist/browser/getClassName.js --source-maps --no-babelrc --plugins transform-es2015-modules-commonjs,transform-flow-strip-types --presets es2015",
     "lint": "eslint ./src && flow",
     "precommit": "npm run test && npm run lint",
-    "test": " NODE_ENV=test mocha --require babel-core/register"
+    "test": " NODE_ENV=test mocha --require babel-core/register",
+    "prepare": "npm install;npm run build"
   },
   "version": "1.0.0"
 }
diff --git a/src/getClassName.js b/src/getClassName.js
index 421787a..fd5a20e 100644
--- a/src/getClassName.js
+++ b/src/getClassName.js
@@ -97,10 +97,11 @@ export default (styleNameValue: string, styleModuleImportMap: StyleModuleImportM
       if (!styleModuleMap[styleName]) {
         if (handleMissingStyleName === 'throw') {
           throw new Error('Could not resolve the styleName \'' + styleName + '\'.');
-        }
-        if (handleMissingStyleName === 'warn') {
+        } else if (handleMissingStyleName === 'warn') {
           // eslint-disable-next-line no-console
           console.warn('Could not resolve the styleName \'' + styleName + '\'.');
+        } else if (handleMissingStyleName === 'retain') {
+          return styleName;
         }
       }
 
diff --git a/src/index.js b/src/index.js
index 2c32aa8..091898f 100644
--- a/src/index.js
+++ b/src/index.js
@@ -10,10 +10,9 @@ import ajvKeywords from 'ajv-keywords';
 import Ajv from 'ajv';
 import optionsSchema from './schemas/optionsSchema.json';
 import optionsDefaults from './schemas/optionsDefaults';
-import createObjectExpression from './createObjectExpression';
 import requireCssModule from './requireCssModule';
 import resolveStringLiteral from './resolveStringLiteral';
-import replaceJsxExpressionContainer from './replaceJsxExpressionContainer';
+import resolveClassnameCallExpression from './resolveClassnameCallExpression';
 
 const ajv = new Ajv({
   // eslint-disable-next-line id-match
@@ -31,44 +30,44 @@ export default ({
 }) => {
   const filenameMap = {};
 
-  const setupFileForRuntimeResolution = (path, filename) => {
-    const programPath = path.findParent((parentPath) => {
-      return parentPath.isProgram();
-    });
-
-    filenameMap[filename].importedHelperIndentifier = programPath.scope.generateUidIdentifier('getClassName');
-    filenameMap[filename].styleModuleImportMapIdentifier = programPath.scope.generateUidIdentifier('styleModuleImportMap');
-
-    programPath.unshiftContainer(
-      'body',
-      t.importDeclaration(
-        [
-          t.importDefaultSpecifier(
-            filenameMap[filename].importedHelperIndentifier
-          )
-        ],
-        t.stringLiteral('babel-plugin-react-css-modules/dist/browser/getClassName')
-      )
-    );
-
-    const firstNonImportDeclarationNode = programPath.get('body').find((node) => {
-      return !t.isImportDeclaration(node);
-    });
-
-    firstNonImportDeclarationNode.insertBefore(
-      t.variableDeclaration(
-        'const',
-        [
-          t.variableDeclarator(
-            filenameMap[filename].styleModuleImportMapIdentifier,
-            createObjectExpression(t, filenameMap[filename].styleModuleImportMap)
-          )
-        ]
-      )
-    );
-    // eslint-disable-next-line no-console
-    // console.log('setting up', filename, util.inspect(filenameMap,{depth: 5}))
-  };
+  // const setupFileForRuntimeResolution = (path, filename) => {
+  //   const programPath = path.findParent((parentPath) => {
+  //     return parentPath.isProgram();
+  //   });
+
+  //   filenameMap[filename].importedHelperIndentifier = programPath.scope.generateUidIdentifier('getClassName');
+  //   filenameMap[filename].styleModuleImportMapIdentifier = programPath.scope.generateUidIdentifier('styleModuleImportMap');
+
+  //   programPath.unshiftContainer(
+  //     'body',
+  //     t.importDeclaration(
+  //       [
+  //         t.importDefaultSpecifier(
+  //           filenameMap[filename].importedHelperIndentifier
+  //         )
+  //       ],
+  //       t.stringLiteral('babel-plugin-react-css-modules/dist/browser/getClassName')
+  //     )
+  //   );
+
+  //   const firstNonImportDeclarationNode = programPath.get('body').find((node) => {
+  //     return !t.isImportDeclaration(node);
+  //   });
+
+  //   firstNonImportDeclarationNode.insertBefore(
+  //     t.variableDeclaration(
+  //       'const',
+  //       [
+  //         t.variableDeclarator(
+  //           filenameMap[filename].styleModuleImportMapIdentifier,
+  //           createObjectExpression(t, filenameMap[filename].styleModuleImportMap)
+  //         )
+  //       ]
+  //     )
+  //   );
+  //   // eslint-disable-next-line no-console
+  //   // console.log('setting up', filename, util.inspect(filenameMap,{depth: 5}))
+  // };
 
   const addWebpackHotModuleAccept = (path) => {
     const test = t.memberExpression(t.identifier('module'), t.identifier('hot'));
@@ -140,6 +139,22 @@ export default ({
   return {
     inherits: babelPluginJsxSyntax,
     visitor: {
+      CallExpression (path: *, stats: *): void {
+        const filename = stats.file.opts.filename;
+
+        const handleMissingStyleName = stats.opts && stats.opts.handleMissingStyleName || optionsDefaults.handleMissingStyleName;
+
+        if (t.isIdentifier(path.node.callee, {name: 'classnames'}) && !t.isJSXExpressionContainer(path.parentPath.node)) {
+          resolveClassnameCallExpression(
+            path,
+            stats,
+            filenameMap[filename].styleModuleImportMap,
+            {
+              handleMissingStyleName
+            }
+          );
+        }
+      },
       ImportDeclaration (path: *, stats: *): void {
         if (notForPlugin(path, stats)) {
           return;
@@ -209,21 +224,6 @@ export default ({
                 handleMissingStyleName
               }
             );
-          } else if (t.isJSXExpressionContainer(attribute.value)) {
-            if (!filenameMap[filename].importedHelperIndentifier) {
-              setupFileForRuntimeResolution(path, filename);
-            }
-            replaceJsxExpressionContainer(
-              t,
-              path,
-              attribute,
-              destinationName,
-              filenameMap[filename].importedHelperIndentifier,
-              filenameMap[filename].styleModuleImportMapIdentifier,
-              {
-                handleMissingStyleName
-              }
-            );
           }
         }
       },
@@ -240,6 +240,18 @@ export default ({
         filenameMap[filename] = {
           styleModuleImportMap: {}
         };
+
+        if (stats.opts.defaultCssFile) {
+          filenameMap[filename] = {
+            styleModuleImportMap: {
+              default: requireCssModule(resolve(stats.opts.defaultCssFile), {
+                context: stats.opts.context,
+                filetypes: stats.opts.filetypes || {},
+                generateScopedName: stats.opts.generateScopedName
+              })
+            }
+          };
+        }
       }
     }
   };
diff --git a/src/requireCssModule.js b/src/requireCssModule.js
index 283718e..76234cc 100644
--- a/src/requireCssModule.js
+++ b/src/requireCssModule.js
@@ -28,6 +28,9 @@ type FiletypesConfigurationType = {
   [key: string]: FiletypeOptionsType
 };
 
+// Cache all tokens generated for each file
+const fileTokensCache = {};
+
 const getFiletypeOptions = (cssSourceFilePath: string, filetypes: FiletypesConfigurationType): ?FiletypeOptionsType => {
   const extension = cssSourceFilePath.substr(cssSourceFilePath.lastIndexOf('.'));
   const filetype = filetypes ? filetypes[extension] : null;
@@ -94,6 +97,9 @@ type OptionsType = {|
 |};
 
 export default (cssSourceFilePath: string, options: OptionsType): StyleModuleMapType => {
+  if (fileTokensCache[cssSourceFilePath]) {
+    return fileTokensCache[cssSourceFilePath];
+  }
   // eslint-disable-next-line prefer-const
   let runner;
 
@@ -132,6 +138,7 @@ export default (cssSourceFilePath: string, options: OptionsType): StyleModuleMap
   ];
 
   runner = postcss(plugins);
+  fileTokensCache[cssSourceFilePath] = getTokens(runner, cssSourceFilePath, filetypeOptions);
 
-  return getTokens(runner, cssSourceFilePath, filetypeOptions);
+  return fileTokensCache[cssSourceFilePath];
 };
diff --git a/src/resolveClassnameCallExpression.js b/src/resolveClassnameCallExpression.js
new file mode 100644
index 0000000..3fdb5b6
--- /dev/null
+++ b/src/resolveClassnameCallExpression.js
@@ -0,0 +1,40 @@
+// @flow
+
+import {
+  isStringLiteral,
+  isObjectExpression
+} from 'babel-types';
+import getClassName from './getClassName';
+import type {
+  StyleModuleImportMapType,
+  HandleMissingStyleNameOptionType
+} from './types';
+
+type OptionsType = {|
+  handleMissingStyleName: HandleMissingStyleNameOptionType
+|};
+
+/**
+ * Updates the className value of a JSX element using a provided styleName attribute.
+ */
+export default (
+  path: *,
+  stats: *,
+  styleModuleImportMap: StyleModuleImportMapType,
+  options: OptionsType): void => {
+  const replaceCallArguments = function (callExpressionArguments) {
+    for (const argument of callExpressionArguments) {
+      if (isStringLiteral(argument)) {
+        argument.value = getClassName(argument.value, styleModuleImportMap, options);
+      } else if (isObjectExpression(argument)) {
+        for (const property of argument.properties) {
+          if (isStringLiteral(property.key)) {
+            property.key.value = getClassName(property.key.value, styleModuleImportMap, options);
+          }
+        }
+      }
+    }
+  };
+
+  replaceCallArguments(path.node.arguments);
+};
diff --git a/src/schemas/optionsSchema.json b/src/schemas/optionsSchema.json
index e14e525..7aa3656 100644
--- a/src/schemas/optionsSchema.json
+++ b/src/schemas/optionsSchema.json
@@ -52,7 +52,7 @@
       "type": "boolean"
     },
     "handleMissingStyleName": {
-      "enum": ["throw", "warn", "ignore"]
+      "enum": ["throw", "warn", "ignore", "retain"]
     },
     "attributeNames": {
       "additionalProperties": false,
@@ -69,6 +69,9 @@
         }
       },
       "type": "object"
+    },
+    "defaultCssFile": {
+      "type": "string"
     }
   },
   "type": "object"