diff --git a/README.md b/README.md
index dbbb1e0..025fc45 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ be done in place, so it is best to either do this in a separate copy of
 the code, or on top of a git repository where you can easily reset --hard
 if you need to.
 
-**Download**: https://github.com/zendframework/Namespacer/blob/master/namespacer.phar?raw=true
+**Download**: https://github.com/dmnc/Namespacer/blob/master/namespacer.phar?raw=true
 
 * First, create a map file:
 
@@ -20,8 +20,19 @@ if you need to.
     namespacer.phar map --mapfile types.php --source path/to/src
     ```
 
-* Second, transform the types located in the map file:
+* Second, if you want to maintain legacy classes extending your new ones:
+
+    ```
+    namespacer.phar legacy --mapfile types.php --target path/for/legacy/files
+    ```
+
+* Thirdly, transform the types located in the map file:
 
     ```
     namespacer.phar transform --mapfile types.php
     ```
+
+* Last, fix any used namespaces
+    ```
+    namespacer.phar fix --mapfile types.php --target path/to/src
+    ```
diff --git a/config/module.config.php b/config/module.config.php
index 566309c..686aa5a 100644
--- a/config/module.config.php
+++ b/config/module.config.php
@@ -59,6 +59,15 @@
                         ),
                     ),
                 ),
+                'namespacer-legacy' => array(
+                    'options' => array(
+                        'route'    => 'legacy [--mapfile=] [--target=]',
+                        'defaults' => array(
+                            'controller' => 'Namespacer\Controller\Controller',
+                            'action'     => 'legacyExtension',
+                        ),
+                    ),
+                ),
             ),
         ),
     ),
diff --git a/src/Namespacer/Controller/Controller.php b/src/Namespacer/Controller/Controller.php
index 5cbf2aa..d15797a 100644
--- a/src/Namespacer/Controller/Controller.php
+++ b/src/Namespacer/Controller/Controller.php
@@ -10,6 +10,7 @@
 use Namespacer\Model\Map;
 use Namespacer\Model\Mapper;
 use Namespacer\Model\Transformer;
+use Namespacer\Model\LegacyExtension;
 use Zend\Mvc\Controller\AbstractActionController;
 
 class Controller extends AbstractActionController
@@ -52,6 +53,17 @@ public function transformAction()
         }
     }
 
+    public function legacyExtensionAction()
+    {
+        $mapfile     = $this->params()->fromRoute('mapfile');
+        $target      = $this->params()->fromRoute('target');
+        $data        = include $mapfile;
+        $map         = new Map($data);
+        $transformer = new LegacyExtension($map);
+
+        $transformer->createLegacyClasses($target);
+    }
+
     public function fixAction()
     {
         $mapfile = $this->params()->fromRoute('mapfile');
diff --git a/src/Namespacer/Model/LegacyExtension.php b/src/Namespacer/Model/LegacyExtension.php
new file mode 100644
index 0000000..a2825ef
--- /dev/null
+++ b/src/Namespacer/Model/LegacyExtension.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace Namespacer\Model;
+
+use Zend\Code\Scanner\FileScanner;
+
+class LegacyExtension
+{
+    /** @var \Namespacer\Model\Map */
+    protected $map;
+
+    public function __construct(Map $map)
+    {
+        $this->map = $map;
+    }
+
+    public function createLegacyClasses($directory = false)
+    {
+        $fileRenamings = $this->map->getExtensionMap($directory);
+
+        foreach ($fileRenamings as $legacyPath => $data) {
+            $legacyDir = dirname($legacyPath);
+            if (!file_exists($legacyDir)) {
+                mkdir($legacyDir, 0777, true);
+            }
+            touch($legacyPath);
+
+            $this->createLegacyFile($legacyPath, $data);
+        }
+    }
+
+    protected function createLegacyFile($file, $data)
+    {
+        $tokens = token_get_all(file_get_contents($data['original_file']));
+
+        $contents = '';
+        $token = reset($tokens);
+        do {
+            if (T_TRAIT === $token[0]) {
+                $contents .= $token[1] . ' ' . $data['class'];
+                $contents .= "\n{\n";
+                $contents .= "    use \\" . $data['extends'] . ";";
+                $contents .= "\n}\n";
+                break;
+            }
+            if (T_CLASS === $token[0] || T_INTERFACE === $token[0]) {
+                $contents .= $token[1] . ' ' . $data['class'];
+                $contents .= " extends \\" . $data['extends'];
+                $contents .= "\n{\n}\n";
+                break;
+            } else {
+                $contents .= (is_array($token)) ? $token[1] : $token;
+            }
+        } while ($token = next($tokens));
+
+        file_put_contents($file, $contents);
+    }
+}
diff --git a/src/Namespacer/Model/Map.php b/src/Namespacer/Model/Map.php
index e1d0493..9f79b97 100644
--- a/src/Namespacer/Model/Map.php
+++ b/src/Namespacer/Model/Map.php
@@ -53,6 +53,24 @@ public function getNewFiles()
         return $data;
     }
 
+    public function getExtensionMap($directory = false)
+    {
+        $data = array();
+        foreach ($this->mapData as $item) {
+            if ($directory) {
+                $file = str_replace($item['root_directory'], $directory, $item['original_file']);
+            } else {
+                $file = $item['original_file'];
+            }
+            $data[$file] = array(
+                'extends' => $item['new_namespace'] . '\\' . $item['new_class'],
+                'class' => $item['original_class'],
+                'original_file' => $item['original_file']
+            );
+        }
+        return $data;
+    }
+
     public function getClassTransformations()
     {
         $data = array();
@@ -61,4 +79,4 @@ public function getClassTransformations()
         }
         return $data;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Namespacer/Model/Transformer.php b/src/Namespacer/Model/Transformer.php
index 285363c..28d56fa 100644
--- a/src/Namespacer/Model/Transformer.php
+++ b/src/Namespacer/Model/Transformer.php
@@ -47,6 +47,17 @@ public function modifyNamespaceAndClassNames()
         }
     }
 
+    public function modifyOriginalContentForExtension()
+    {
+        $extensionMap = $this->map->getExtensionMap();
+        foreach ($extensionMap as $file => $extends) {
+            if (!file_exists($file)) {
+                throw new \RuntimeException('The file ' . $file . ' could not be found in the filesystem, check your map file is correct.');
+            }
+            $this->modifyOriginalFileforExtension($file, $extends);
+        }
+    }
+
     public function modifyContentForUseStatements()
     {
         $files = $this->map->getNewFiles();
@@ -103,6 +114,33 @@ protected function modifyFileWithNewNamespaceAndClass($file, $names)
         file_put_contents($file, $contents);
     }
 
+    protected function modifyOriginalFileforExtension($file, $names)
+    {
+        $tokens = token_get_all(file_get_contents($file));
+
+        $contents = '';
+        $token = reset($tokens);
+        do {
+            if (T_TRAIT === $token[0]) {
+                $contents .= $token[1] . ' ' . $names['class'];
+                $contents .= "\n{\n";
+                $contents .= "    use \\" . $names['extends'] . ";";
+                $contents .= "\n}\n";
+                break 2;
+            }
+            if ($this->isClass($token[0])) {
+                $contents .= $token[1] . ' ' . $names['class'];
+                $contents .= " extends \\" . $names['extends'];
+                $contents .= "\n{\n}\n";
+                break 2;
+            } else {
+                $contents .= (is_array($token)) ? $token[1] : $token;
+            }
+        } while ($token = next($tokens));
+
+        file_put_contents($file, $contents);
+    }
+
     protected function modifyFileWithNewUseStatements($file, $classTransformations)
     {
         $tokens = token_get_all(file_get_contents($file));