diff --git a/cache/stores/memcache/addinstanceform.php b/cache/stores/memcache/addinstanceform.php
index deb4c9b0f9b..edd55d7eca6 100644
--- a/cache/stores/memcache/addinstanceform.php
+++ b/cache/stores/memcache/addinstanceform.php
@@ -46,5 +46,11 @@ class cachestore_memcache_addinstance_form extends cachestore_addinstance_form {
         $form->addHelpButton('servers', 'servers', 'cachestore_memcache');
         $form->addRule('servers', get_string('required'), 'required');
         $form->setType('servers', PARAM_RAW);
+
+        $form->addElement('text', 'prefix', get_string('prefix', 'cachestore_memcache'),
+                array('maxlength' => 5, 'size' => 5));
+        $form->addHelpButton('prefix', 'prefix', 'cachestore_memcache');
+        $form->setType('prefix', PARAM_ALPHAEXT);
+        $form->setDefault('prefix', 'mdl_');
     }
 }
\ No newline at end of file
diff --git a/cache/stores/memcache/lang/en/cachestore_memcache.php b/cache/stores/memcache/lang/en/cachestore_memcache.php
index 585fd53773c..5cba887de78 100644
--- a/cache/stores/memcache/lang/en/cachestore_memcache.php
+++ b/cache/stores/memcache/lang/en/cachestore_memcache.php
@@ -27,6 +27,10 @@
 defined('MOODLE_INTERNAL') || die();
 
 $string['pluginname'] = 'Memcache';
+$string['prefix'] = 'Key prefix';
+$string['prefix_help'] = 'This prefix is used for all key names on the memcache server.
+* If you only have one Moodle instance using this server, you can leave this value default.
+* Due to key length restrictions, a maximum of 5 characters is permitted.';
 $string['servers'] = 'Servers';
 $string['servers_help'] = 'This sets the servers that should be utilised by this memcache adapter.
 Servers should be defined one per line and consist of a server address and optionally a port and weight.
diff --git a/cache/stores/memcache/lib.php b/cache/stores/memcache/lib.php
index f8a21b8a3ce..882ab3775cb 100644
--- a/cache/stores/memcache/lib.php
+++ b/cache/stores/memcache/lib.php
@@ -51,6 +51,12 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
      */
     protected $connection;
 
+    /**
+     * Key prefix for this memcache.
+     * @var string
+     */
+    protected $prefix;
+
     /**
      * An array of servers to use in the connection args.
      * @var array
@@ -81,6 +87,12 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
      */
     protected $definition;
 
+    /**
+     * Default prefix for key names.
+     * @var string
+     */
+    const DEFAULT_PREFIX = 'mdl_';
+
     /**
      * Constructs the store instance.
      *
@@ -111,6 +123,11 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
             }
             $this->servers[] = $server;
         }
+        if (empty($configuration['prefix'])) {
+            $this->prefix = self::DEFAULT_PREFIX;
+        } else {
+            $this->prefix = $configuration['prefix'];
+        }
 
         $this->connection = new Memcache;
         foreach ($this->servers as $server) {
@@ -212,7 +229,7 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
         if (strlen($key) > 245) {
             $key = '_sha1_'.sha1($key);
         }
-        $key = 'mdl_'.$key;
+        $key = $this->prefix . $key;
         return $key;
     }
 
@@ -338,6 +355,7 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
         }
         return array(
             'servers' => $servers,
+            'prefix' => $data->prefix,
         );
     }
 
@@ -356,6 +374,12 @@ class cachestore_memcache extends cache_store implements cache_is_configurable {
             }
             $data['servers'] = join("\n", $servers);
         }
+        if (!empty($config['prefix'])) {
+            $data['prefix'] = $config['prefix'];
+        } else {
+            $data['prefix'] = self::DEFAULT_PREFIX;
+        }
+
         $editform->set_data($data);
     }
 
diff --git a/cache/stores/memcache/version.php b/cache/stores/memcache/version.php
index f986c2a76a6..b11b08a05b7 100644
--- a/cache/stores/memcache/version.php
+++ b/cache/stores/memcache/version.php
@@ -26,6 +26,6 @@
 
 defined('MOODLE_INTERNAL') || die;
 
-$plugin->version = 2013050100;    // The current module version (Date: YYYYMMDDXX)
+$plugin->version = 2013050700;    // The current module version (Date: YYYYMMDDXX)
 $plugin->requires = 2013050100;    // Requires this Moodle version.
-$plugin->component = 'cachestore_memcache';  // Full name of the plugin.
\ No newline at end of file
+$plugin->component = 'cachestore_memcache';  // Full name of the plugin.