diff --git a/Security/Authorization/Expression/Ast/GetItemExpression.php b/Security/Authorization/Expression/Ast/GetItemExpression.php
index 2df5eb0..38ab4be 100644
--- a/Security/Authorization/Expression/Ast/GetItemExpression.php
+++ b/Security/Authorization/Expression/Ast/GetItemExpression.php
@@ -18,7 +18,7 @@
 
 namespace JMS\SecurityExtraBundle\Security\Authorization\Expression\Ast;
 
-class GetItemExpression
+class GetItemExpression implements ExpressionInterface
 {
     public $array;
     public $key;
@@ -28,4 +28,4 @@ public function __construct(ExpressionInterface $array, ExpressionInterface $key
         $this->array = $array;
         $this->key = $key;
     }
-}
\ No newline at end of file
+}
diff --git a/Security/Authorization/Expression/ExpressionCompiler.php b/Security/Authorization/Expression/ExpressionCompiler.php
index 9b0a6d8..81afeb5 100644
--- a/Security/Authorization/Expression/ExpressionCompiler.php
+++ b/Security/Authorization/Expression/ExpressionCompiler.php
@@ -274,6 +274,14 @@ public function compilePreconditions(ExpressionInterface $expr)
             return $this;
         }
 
+        if ($expr instanceof GetItemExpression) {
+            $this
+                ->compilePreconditions($expr->array)
+                ->compilePreconditions($expr->key);
+
+            return $this;
+        }
+
         if ($expr instanceof GetPropertyExpression) {
             $this->compilePreconditions($expr->object);
 
@@ -317,7 +325,9 @@ public function compileInternal(ExpressionInterface $expr)
 
         if ($expr instanceof GetItemExpression) {
             $this->compileInternal($expr->array);
-            $this->code .= '['.$expr->key.']';
+            $this->code .= '[';
+            $this->compileInternal($expr->key);
+            $this->code .= ']';
 
             return $this;
         }
diff --git a/Tests/Security/Authorization/Expression/GetItemExpressionCompilerTest.php b/Tests/Security/Authorization/Expression/GetItemExpressionCompilerTest.php
new file mode 100644
index 0000000..deaad51
--- /dev/null
+++ b/Tests/Security/Authorization/Expression/GetItemExpressionCompilerTest.php
@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * Copyright 2011 Johannes M. Schmitt <schmittjoh@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace JMS\SecurityExtraBundle\Tests\Security\Authorization\Expression;
+
+use JMS\SecurityExtraBundle\Security\Authorization\Expression\Expression;
+use JMS\SecurityExtraBundle\Security\Authorization\Expression\ExpressionCompiler;
+
+class GetItemExpressionCompilerTest extends \PHPUnit_Framework_TestCase
+{
+    private $compiler;
+
+    public function testCompile()
+    {
+        $evaluator = eval($source = $this->compiler->compileExpression(new Expression(
+            'object["foo"] == "bar"')));
+
+        $this->assertTrue($evaluator(array('object' => array('foo' => 'bar'))));
+
+        $this->assertFalse($evaluator(array('object' => array('foo' => 'baz'))));
+    }
+
+    public function testCompileWithComplexKey()
+    {
+        $evaluator = eval($source = $this->compiler->compileExpression(new Expression(
+            'object[key] == "bar"')));
+
+        $this->assertTrue($evaluator(array('object' => array('foo' => 'bar'), 'key' => 'foo')));
+
+        $this->assertFalse($evaluator(array('object' => array('foo' => 'baz'), 'key' => 'foo')));
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testCompilePreconditionsForKey()
+    {
+        $evaluator = eval($source = $this->compiler->compileExpression(new Expression(
+            'object[key] == "bar"')));
+
+        $evaluator(array('object' => array('foo' => 'bar')));
+    }
+
+    /**
+     * @expectedException \RuntimeException
+     */
+    public function testCompilePreconditionsForArray()
+    {
+        $evaluator = eval($source = $this->compiler->compileExpression(new Expression(
+            'object[key] == "bar"')));
+
+        $evaluator(array('key' => 'foo'));
+    }
+
+    protected function setUp()
+    {
+        $this->compiler = new ExpressionCompiler();
+    }
+}