diff --git a/lib/Doctrine/Common/Annotations/Lexer.php b/lib/Doctrine/Common/Annotations/Lexer.php
index 571be910d..d624a1bd8 100644
--- a/lib/Doctrine/Common/Annotations/Lexer.php
+++ b/lib/Doctrine/Common/Annotations/Lexer.php
@@ -91,10 +91,8 @@ class Lexer extends \Doctrine\Common\Lexer
             $value = str_replace('""', '"', substr($value, 1, strlen($value) - 2));
             
             return self::T_STRING;
-        } else if (ctype_alpha($value[0]) || $value[0] === '_') {
-            return $this->_checkLiteral($value);
         } else {
-            switch ($value) {
+            switch (strtolower($value)) {
                 case '@': return self::T_AT;
                 case ',': return self::T_COMMA;
                 case '(': return self::T_OPEN_PARENTHESIS;
@@ -103,8 +101,13 @@ class Lexer extends \Doctrine\Common\Lexer
                 case '}': return self::T_CLOSE_CURLY_BRACES;
                 case '=': return self::T_EQUALS;
                 case '\\': return self::T_NAMESPACE_SEPARATOR;
+                case 'true': return self::T_TRUE;
+                case 'false': return self::T_FALSE;
                 default:
-                    // Do nothing
+                    if (ctype_alpha($value[0]) || $value[0] === '_') {
+                        return self::T_IDENTIFIER;
+                    }
+                    
                     break;
             }
         }
@@ -130,21 +133,4 @@ class Lexer extends \Doctrine\Common\Lexer
 
         return false;
     }
-    
-    /**
-     * Checks if an identifier is a keyword and returns its correct type.
-     *
-     * @param string $identifier identifier name
-     * @return integer token type
-     */
-    private function _checkLiteral($identifier)
-    {
-        $name = 'Doctrine\Common\Annotations\Lexer::T_' . strtoupper($identifier);
-
-        if (defined($name)) {
-            return constant($name);
-        }
-
-        return self::T_IDENTIFIER;
-    }
 }
\ No newline at end of file
diff --git a/tests/Doctrine/Tests/Common/Annotations/ParserTest.php b/tests/Doctrine/Tests/Common/Annotations/ParserTest.php
index b1f7a292c..270517d55 100644
--- a/tests/Doctrine/Tests/Common/Annotations/ParserTest.php
+++ b/tests/Doctrine/Tests/Common/Annotations/ParserTest.php
@@ -122,6 +122,31 @@ DOCBLOCK;
         $parser = $this->createTestParser();
         $parser->parse("@Name(foo='bar')", "class \Doctrine\Tests\Common\Annotations\Name");
     }
+    
+    /**
+     * @group DDC-183
+     */
+    public function testSyntaxErrorWithUnknownCharacters()
+    {
+        $docblock = <<<DOCBLOCK
+/**
+ * @test at.
+ */
+class A {
+}
+DOCBLOCK;
+        
+        //$lexer = new \Doctrine\Common\Annotations\Lexer();
+        //$lexer->setInput(trim($docblock, '/ *'));
+        //var_dump($lexer);
+        
+        try {
+            $parser = $this->createTestParser();
+            $result = $parser->parse($docblock);
+        } catch (Exception $e) {
+            $this->fail($e->getMessage());
+        }
+    }
 }
 
 class Name extends \Doctrine\Common\Annotations\Annotation {