diff --git a/src/Value/Size.php b/src/Value/Size.php
index 9329f15b..36a32381 100644
--- a/src/Value/Size.php
+++ b/src/Value/Size.php
@@ -77,9 +77,16 @@ public static function parse(ParserState $oParserState, $bIsColorComponent = fal
         if ($oParserState->comes('-')) {
             $sSize .= $oParserState->consume('-');
         }
-        while (is_numeric($oParserState->peek()) || $oParserState->comes('.')) {
+        while (is_numeric($oParserState->peek()) || $oParserState->comes('.') || $oParserState->comes('e', true)) {
             if ($oParserState->comes('.')) {
                 $sSize .= $oParserState->consume('.');
+            } elseif ($oParserState->comes('e', true)) {
+                $sLookahead = $oParserState->peek(1, 1);
+                if (is_numeric($sLookahead) || $sLookahead === '+' || $sLookahead === '-') {
+                    $sSize .= $oParserState->consume(2);
+                } else {
+                    break; // Reached the unit part of the number like "em" or "ex"
+                }
             } else {
                 $sSize .= $oParserState->consume(1);
             }
diff --git a/tests/ParserTest.php b/tests/ParserTest.php
index 5e2a3101..012ab667 100644
--- a/tests/ParserTest.php
+++ b/tests/ParserTest.php
@@ -1171,6 +1171,21 @@ public function largeSizeValuesInFile()
         self::assertSame($sExpected, $oDoc->render());
     }
 
+    /**
+     * @test
+     */
+    public function scientificNotationSizeValuesInFile()
+    {
+        $oDoc = $this->parsedStructureForFile(
+            'scientific-notation-numbers',
+            Settings::create()->withMultibyteSupport(false)
+        );
+        $sExpected = ''
+            . 'body {background-color: rgba(62,174,151,3041820656523200167936);'
+            . 'z-index: .030418206565232;font-size: 1em;top: 192.3478px;}';
+        self::assertSame($sExpected, $oDoc->render());
+    }
+
     /**
      * @test
      */
diff --git a/tests/fixtures/scientific-notation-numbers.css b/tests/fixtures/scientific-notation-numbers.css
new file mode 100644
index 00000000..cbed2337
--- /dev/null
+++ b/tests/fixtures/scientific-notation-numbers.css
@@ -0,0 +1,6 @@
+body {
+  background-color: rgba(62,174,151,3.0418206565232E+21);
+  z-index: 3.0418206565232E-2;
+  font-size: 1em;
+  top: 1.923478e2px;
+}