diff --git a/composer.json b/composer.json
index 5d2df54..b4bc34b 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "homepage": "https://github.com/php-curl-class/php-curl-class",
     "license": "Unlicense",
     "keywords": ["php", "curl", "class"],
-    "version": "2.1.2",
+    "version": "2.1.3",
     "require": {
         "php": ">=5.3",
         "ext-curl": "*"
diff --git a/src/Curl/Curl.php b/src/Curl/Curl.php
index 2659b26..e85bc09 100644
--- a/src/Curl/Curl.php
+++ b/src/Curl/Curl.php
@@ -4,7 +4,7 @@ namespace Curl;
 
 class Curl
 {
-    const VERSION = '2.1.2';
+    const VERSION = '2.1.3';
 
     private $cookies = array();
     private $headers = array();
@@ -413,7 +413,15 @@ class Curl
     {
         if (is_array($data)) {
             if (self::is_array_multidim($data)) {
-                $data = self::http_build_multi_query($data);
+                if (isset($this->headers['Content-Type']) &&
+                    preg_match($this->json_pattern, $this->headers['Content-Type'])) {
+                    $json_str = json_encode($data);
+                    if (!($json_str === false)) {
+                        $data = $json_str;
+                    }
+                } else {
+                    $data = self::http_build_multi_query($data);
+                }
             } else {
                 $binary_data = false;
                 foreach ($data as $key => $value) {
diff --git a/tests/PHPCurlClass/PHPCurlClassTest.php b/tests/PHPCurlClass/PHPCurlClassTest.php
index 39f8937..51090f7 100644
--- a/tests/PHPCurlClass/PHPCurlClassTest.php
+++ b/tests/PHPCurlClass/PHPCurlClassTest.php
@@ -644,31 +644,51 @@ class CurlTest extends PHPUnit_Framework_TestCase
 
     public function testJSONRequest()
     {
-        $data = array('key' => 'value');
-        $expected_response = '{"key":"value"}';
+        foreach (
+            array(
+                array(
+                    array(
+                        'key' => 'value',
+                    ),
+                    '{"key":"value"}',
+                ),
+                array(
+                    array(
+                        'key' => 'value',
+                        'strings' => array(
+                            'a',
+                            'b',
+                            'c',
+                        ),
+                    ),
+                    '{"key":"value","strings":["a","b","c"]}',
+                ),
+            ) as $test) {
+            list($data, $expected_response) = $test;
 
-        $test = new Test();
-        $this->assertEquals($expected_response, $test->server('post_json', 'POST', json_encode($data)));
+            $test = new Test();
+            $this->assertEquals($expected_response, $test->server('post_json', 'POST', json_encode($data)));
 
-        foreach (array(
-            'Content-Type',
-            'content-type',
-            'CONTENT-TYPE') as $key) {
             foreach (array(
-                'APPLICATION/JSON',
-                'APPLICATION/JSON; CHARSET=UTF-8',
-                'APPLICATION/JSON;CHARSET=UTF-8',
-                'application/json',
-                'application/json; charset=utf-8',
-                'application/json;charset=UTF-8',
-                ) as $value) {
-                $test = new Test();
-                $test->curl->setHeader($key, $value);
-                $this->assertEquals($expected_response, $test->server('post_json', 'POST', json_encode($data)));
+                'Content-Type',
+                'content-type',
+                'CONTENT-TYPE') as $key) {
+                foreach (array(
+                    'APPLICATION/JSON',
+                    'APPLICATION/JSON; CHARSET=UTF-8',
+                    'APPLICATION/JSON;CHARSET=UTF-8',
+                    'application/json',
+                    'application/json; charset=utf-8',
+                    'application/json;charset=UTF-8',
+                    ) as $value) {
+                    $test = new Test();
+                    $test->curl->setHeader($key, $value);
+                    $this->assertEquals($expected_response, $test->server('post_json', 'POST', json_encode($data)));
 
-                $test = new Test();
-                $test->curl->setHeader($key, $value);
-                $this->assertEquals($expected_response, $test->server('post_json', 'POST', $data));
+                    $test = new Test();
+                    $test->curl->setHeader($key, $value);
+                    $this->assertEquals($expected_response, $test->server('post_json', 'POST', $data));
+                }
             }
         }
     }