diff --git a/action/Request.php b/action/Request.php
index b427e0e37e..690ee7a2f3 100644
--- a/action/Request.php
+++ b/action/Request.php
@@ -620,9 +620,17 @@ public function is($flag) {
 
 	/**
 	 * Sets/Gets the content type. If `'type'` is null, the method will attempt to determine the
-	 * type from the params, then from the environment setting
+	 * type from the params, then from the environment setting.
 	 *
-	 * @param string $type a full content type i.e. `'application/json'` or simple name `'json'`
+	 * Handle the case where a single type could not be determined by a call to
+	 * `lithium\net\http\Media::type` in `lithium\net\nttp\Message::type`.
+	 * In that case, the value of `$type` is returned from the parent as it
+	 * was passed in. Attempt to use `lithium\net\http\Media::match` to
+	 * distinguish which type to use for the request. The type is later used to
+	 * decode the request body. Not handling this case leads to the correct
+	 * type's decoder not being invoked on the body of the request.
+	 *
+	 * @param string $type A full content type i.e. `'application/json'` or simple name `'json'`
 	 * @return string A simple content type name, i.e. `'html'`, `'xml'`, `'json'`, etc., depending
 	 *         on the content type of the request.
 	 */
@@ -630,7 +638,22 @@ public function type($type = null) {
 		if (!$type && !empty($this->params['type'])) {
 			$type = $this->params['type'];
 		}
-		return parent::type($type);
+		$_type = parent::type($type);
+		if (is_string($type) && $_type === $type) {
+			$media = $this->_classes['media'];
+			$content = $media::type($type);
+			if (is_array($content) && !isset($content['content'])) {
+				foreach ($content as $short_type) {
+					$conf = $media::type($short_type);
+					$conf['name'] = $short_type;
+					if ($media::match($this, $conf)) {
+						$_type = $short_type;
+						break;
+					}
+				}
+			}
+		}
+		return ($this->_type = $_type);
 	}
 
 	/**
@@ -803,4 +826,4 @@ protected function _parseFiles($data) {
 	}
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/net/http/Request.php b/net/http/Request.php
index 695a1709a1..7fa35098d9 100644
--- a/net/http/Request.php
+++ b/net/http/Request.php
@@ -355,4 +355,4 @@ public function __toString() {
 	}
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/net/http/Response.php b/net/http/Response.php
index bd2f01a288..b4f5a3e679 100644
--- a/net/http/Response.php
+++ b/net/http/Response.php
@@ -147,7 +147,7 @@ public function __construct(array $config = []) {
 		$header = is_array($header) ? end($header) : $header;
 		preg_match('/([-\w\/\.+]+)(;\s*?charset=(.+))?/i', $header, $match);
 
-		if (isset($match[1])) {
+		if (!$this->_type && isset($match[1])) {
 			$this->type(trim($match[1]));
 		}
 		if (isset($match[3])) {
@@ -437,4 +437,4 @@ public function __toString() {
 	}
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/tests/cases/action/RequestTest.php b/tests/cases/action/RequestTest.php
index d9c22f6294..c1a41ee5e1 100644
--- a/tests/cases/action/RequestTest.php
+++ b/tests/cases/action/RequestTest.php
@@ -11,6 +11,7 @@
 
 use lithium\core\Libraries;
 use lithium\action\Request;
+use lithium\net\http\Media;
 
 class RequestTest extends \lithium\test\Unit {
 
@@ -83,6 +84,7 @@ public function tearDown() {
 		foreach ($this->_superglobals as $varname) {
 			$GLOBALS[$varname] = $this->_env[$varname];
 		}
+		Media::reset();
 	}
 
 	public function testInitData() {
@@ -488,6 +490,34 @@ public function testContentTypeDetection() {
 		$this->assertFalse($request->is('foo'));
 	}
 
+	public function testContentTypeDetectionWithMultipleChoices() {
+		Media::type('json_base64', ['application/json'], [
+			'encode' => function ($data) {
+				return base64_encode(json_encode($data));
+			},
+			'decode' => function ($data) {
+				return json_decode(base64_decode($data), true);
+			},
+			'cast' => true,
+			'conditions' => [
+				'http:content_transfer_encoding' => 'base64'
+			]
+		]);
+		$request = new Request(['env' => [
+			'CONTENT_TYPE' => 'application/json; charset=UTF-8',
+			'REQUEST_METHOD' => 'POST'
+		]]);
+		$this->assertTrue($request->is('json'));
+		$this->assertFalse($request->is('json_base64'));
+		$request = new Request(['env' => [
+			'CONTENT_TYPE' => 'application/json; charset=UTF-8',
+			'REQUEST_METHOD' => 'POST',
+			'HTTP_CONTENT_TRANSFER_ENCODING' => 'base64'
+		]]);
+		$this->assertTrue($request->is('json_base64'));
+		$this->assertFalse($request->is('json'));
+	}
+
 	public function testIsMobile() {
 		$iPhone = 'Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like ';
 		$iPhone .= 'Gecko) Version/3.0 Mobile/1A535b Safari/419.3';
@@ -1596,4 +1626,4 @@ public function testOverridingOfEnvVariables() {
 	}
 }
 
-?>
\ No newline at end of file
+?>