diff --git a/httprl.module b/httprl.module
index a38c381..2f8f4b8 100644
--- a/httprl.module
+++ b/httprl.module
@@ -83,6 +83,11 @@ define('HTTPRL_REQUEST_TIMEOUT', -10060);
 define('HTTPRL_CONNECTION_REFUSED', -10061);
 
 /**
+ * HTTP encapsulation boundary string.
+ */
+define('HTTPRL_MULTIPART_BOUNDARY', '---------------------------' . str_replace('.','', microtime(TRUE)));
+
+/**
  * Implement hook_menu().
  */
 function httprl_menu() {
@@ -464,8 +469,64 @@ function httprl_set_connection_flag(&$options, $uri) {
  */
 function httprl_handle_data(&$options) {
   // Encode data if not already done.
-  if (!is_null($options['data']) && !is_string($options['data'])) {
-    $options['data'] = http_build_query($options['data'], '', '&');
+  if (!empty($options['data']) && !is_string($options['data'])) {
+    // No files passed in, url-encode the data.
+    if (empty($options['data']['files']) || !is_array($options['data']['files'])) {
+      $options['data'] = http_build_query($options['data'], '', '&');
+
+      // Set the Content-Type to application/x-www-form-urlencoded if the data
+      // is not empty, the Content-Type is not set, and the method is POST or
+      // PUT.
+      if (!empty($options['data']) && !isset($options['headers']['Content-Type']) && ($options['method'] == 'POST' || $options['method'] == 'PUT')) {
+        $options['headers']['Content-Type'] = 'application/x-www-form-urlencoded';
+      }
+    }
+    else {
+      $data_stream = '';
+      // Add files to the request.
+      foreach ($options['data']['files'] as $field_name => $info) {
+        $multi_field = '[]';
+        // Convert $info into an array if it's a string.
+        // This makes for one code path (the foreach loop).
+        if (is_string($info)) {
+          $multi_field = '';
+          $temp = $info;
+          unset($info);
+          $info[] = $temp;
+        }
+        foreach ($info as $fullpath) {
+          // Strip '@' from the start of the path (cURL requirement).
+          if (substr($fullpath, 0, 1) == "@") {
+            $fullpath = substr($fullpath, 1);
+          }
+          $filename = basename($fullpath);
+          // TODO: mime detection.
+          $mimetype = 'application/octet-stream';
+
+          // Build the datastream for this file.
+          $data_stream .= '--' . HTTPRL_MULTIPART_BOUNDARY . "\r\n";
+          $data_stream .= 'Content-Disposition: form-data; name="files[' . $field_name . ']' . $multi_field . '"; filename="' . $filename .  "\"\r\n";
+          $data_stream .= 'Content-Transfer-Encoding: binary' . "\r\n";
+          $data_stream .= 'Content-Type: ' . $mimetype . "\r\n\r\n";
+          $data_stream .= file_get_contents($fullpath) . "\r\n";
+        }
+      }
+      // Remove files from the data array as they have already been added.
+      $data_array = $options['data'];
+      unset($data_array['files']);
+      // Add fields to the request too: $_POST['foo'] = 'bar'.
+      httprl_multipart_encoder($data_stream, $data_array);
+
+      // Signal end of request (note the trailing "--").
+      $data_stream .= '--' . HTTPRL_MULTIPART_BOUNDARY . "--\r\n";
+      $options['data'] = $data_stream;
+
+      // Set the Content-Type to multipart/form-data if the data is not empty,
+      // the Content-Type is not set, and the method is POST or PUT.
+      if (!empty($options['data']) && !isset($options['headers']['Content-Type']) && ($options['method'] == 'POST' || $options['method'] == 'PUT')) {
+        $options['headers']['Content-Type'] = 'multipart/form-data; boundary=' . HTTPRL_MULTIPART_BOUNDARY;
+      }
+    }
   }
 
   // Only add Content-Length if we actually have any content or if it is a POST
@@ -476,11 +537,33 @@ function httprl_handle_data(&$options) {
   if ($content_length > 0 || $options['method'] == 'POST' || $options['method'] == 'PUT') {
     $options['headers']['Content-Length'] = $content_length;
   }
+}
 
-  // Set the Content-Type to application/x-www-form-urlencoded if the data is
-  // not empty, the Content-Type is not set, and the method is POST.
-  if ($content_length > 0 && !isset($options['headers']['Content-Type']) && $options['method'] == 'POST') {
-    $options['headers']['Content-Type'] = 'application/x-www-form-urlencoded';
+/**
+ * Multipart encode a data array.
+ *
+ * PHP has http_build_query() which will url-encode data. There is no built in function to multipart encode data thus we have this function below.
+ * @param $uri
+ *   Array from parse_url().
+ * @param &$options
+ *   Array containing options.
+ */
+function httprl_multipart_encoder(&$data_stream, $data_array, $prepend = array()) {
+  foreach ($data_array as $key => $value) {
+    $key_array = $prepend;
+    $key_array[] = $key;
+    if (is_array($value)) {
+      httprl_multipart_encoder($data_stream, $value, $key_array);
+    }
+    elseif (is_scalar($value)) {
+      $key_string = array_shift($key_array);
+      if (!empty($key_array)) {
+        $key_string .= '[' . implode('][', $key_array) . ']';
+      }
+      $data_stream .= '--' . HTTPRL_MULTIPART_BOUNDARY . "\r\n";
+      $data_stream .= 'Content-Disposition: form-data; name="' . $key_string . "\"\r\n\r\n";
+      $data_stream .= $value . "\r\n";
+    }
   }
 }