diff --git a/commerce_paypal.module b/commerce_paypal.module
index 107247a..985424a 100644
--- a/commerce_paypal.module
+++ b/commerce_paypal.module
@@ -84,7 +84,7 @@ function commerce_paypal_process_ipn($payment_method = NULL, $debug_ipn = array(
     }
 
     // Process the HTTP request to validate the IPN.
-    $response = drupal_http_request($host, array(), 'POST', implode('&', $variables));
+    $response = drupal_http_request($host, array('method' => 'POST', 'data' => implode('&', $variables)));
 
     // If an error occurred during processing, log the message and exit.
     if (property_exists($response, 'error')) {