diff --git a/src/Symfony/Component/Process/Process.php b/src/Symfony/Component/Process/Process.php
index 66310026b3..5fe56c566f 100644
--- a/src/Symfony/Component/Process/Process.php
+++ b/src/Symfony/Component/Process/Process.php
@@ -876,9 +876,15 @@ class Process
      * @param string|null $stdin The new contents
      *
      * @return self The current Process instance
+     *
+     * @throws LogicException In case the process is running
      */
     public function setStdin($stdin)
     {
+        if ($this->isRunning()) {
+            throw new LogicException('STDIN can not be set while the process is running.');
+        }
+
         $this->stdin = $stdin;
 
         return $this;
diff --git a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
index 738319e24c..3fac141080 100644
--- a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Process\Tests;
 
+use Symfony\Component\Process\Exception\LogicException;
 use Symfony\Component\Process\Process;
 use Symfony\Component\Process\Exception\RuntimeException;
 use Symfony\Component\Process\ProcessPipes;
@@ -156,6 +157,20 @@ abstract class AbstractProcessTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($expectedLength, strlen($p->getErrorOutput()));
     }
 
+    public function testSetStdinWhileRunningThrowsAnException()
+    {
+        $process = $this->getProcess('php -r "usleep(500000);"');
+        $process->start();
+        try {
+            $process->setStdin('foobar');
+            $process->stop();
+            $this->fail('A LogicException should have been raised.');
+        } catch (LogicException $e) {
+            $this->assertEquals('STDIN can not be set while the process is running.', $e->getMessage());
+        }
+        $process->stop();
+    }
+
     public function chainedCommandsOutputProvider()
     {
         if (defined('PHP_WINDOWS_VERSION_BUILD')) {