diff --git a/src/Symfony/Component/Process/ProcessBuilder.php b/src/Symfony/Component/Process/ProcessBuilder.php
index 23d98b504f..ddd064a2b8 100644
--- a/src/Symfony/Component/Process/ProcessBuilder.php
+++ b/src/Symfony/Component/Process/ProcessBuilder.php
@@ -154,14 +154,14 @@ class ProcessBuilder
 
     public function getProcess()
     {
-        if (!count($this->arguments)) {
+        if (!$this->prefix && !count($this->arguments)) {
             throw new LogicException('You must add() command arguments before calling getProcess().');
         }
 
         $options = $this->options;
 
-        $script = ($this->prefix ? escapeshellarg($this->prefix) . ' ' : '')
-            .implode(' ', array_map(array(__NAMESPACE__.'\\ProcessUtils', 'escapeArgument'), $this->arguments));
+        $arguments = $this->prefix ? array_merge(array($this->prefix), $this->arguments) : $this->arguments;
+        $script = implode(' ', array_map(array(__NAMESPACE__.'\\ProcessUtils', 'escapeArgument'), $arguments));
 
         if ($this->inheritEnv) {
             $env = $this->env ? $this->env + $_ENV : null;
diff --git a/src/Symfony/Component/Process/Tests/ProcessBuilderTest.php b/src/Symfony/Component/Process/Tests/ProcessBuilderTest.php
index e585eb411c..eea028a406 100644
--- a/src/Symfony/Component/Process/Tests/ProcessBuilderTest.php
+++ b/src/Symfony/Component/Process/Tests/ProcessBuilderTest.php
@@ -139,4 +139,42 @@ class ProcessBuilderTest extends \PHPUnit_Framework_TestCase
             $this->assertSame("'%path%' 'foo \" bar'", $proc->getCommandLine());
         }
     }
+
+    public function testShouldEscapeArgumentsAndPrefix()
+    {
+        $pb = new ProcessBuilder(array('arg'));
+        $pb->setPrefix('%prefix%');
+        $proc = $pb->getProcess();
+
+        if (defined('PHP_WINDOWS_VERSION_BUILD')) {
+            $this->assertSame('^%"prefix"^% "arg"', $proc->getCommandLine());
+        } else {
+            $this->assertSame("'%prefix%' 'arg'", $proc->getCommandLine());
+        }
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Process\Exception\LogicException
+     */
+    public function testShouldThrowALogicExceptionIfNoPrefixAndNoArgument()
+    {
+        ProcessBuilder::create()->getProcess();
+    }
+
+    public function testShouldNotThrowALogicExceptionIfNoArgument()
+    {
+        $process = ProcessBuilder::create()
+            ->setPrefix('/usr/bin/php')
+            ->getProcess();
+
+        $this->assertEquals("'/usr/bin/php'", $process->getCommandLine());
+    }
+
+    public function testShouldNotThrowALogicExceptionIfNoPrefix()
+    {
+        $process = ProcessBuilder::create(array('/usr/bin/php'))
+            ->getProcess();
+
+        $this->assertEquals("'/usr/bin/php'", $process->getCommandLine());
+    }
 }