diff --git a/lib/Cake/I18n/I18n.php b/lib/Cake/I18n/I18n.php
index 9215137e4..16fb9983d 100644
--- a/lib/Cake/I18n/I18n.php
+++ b/lib/Cake/I18n/I18n.php
@@ -87,6 +87,68 @@ class I18n {
 		'LC_ALL', 'LC_COLLATE', 'LC_CTYPE', 'LC_MONETARY', 'LC_NUMERIC', 'LC_TIME', 'LC_MESSAGES'
 	);
 
+/**
+ * Constants for the translation categories.
+ *
+ * The constants may be used in translation fetching
+ * instead of hardcoded integers.
+ * Example:
+ * {{{
+ *	I18n::translate('CakePHP is awesome.', null, null, I18n::LC_MESSAGES)
+ * }}}
+ *
+ * To keep the code more readable, I18n constants are preferred over
+ * hardcoded integers.
+ */
+/**
+ * Constant for LC_ALL.
+ *
+ * @var int
+ */
+	const LC_ALL = 0;
+
+/**
+ * Constant for LC_COLLATE.
+ *
+ * @var int
+ */
+	const LC_COLLATE = 1;
+
+/**
+ * Constant for LC_CTYPE.
+ *
+ * @var int
+ */
+	const LC_CTYPE = 2;
+
+/**
+ * Constant for LC_MONETARY.
+ *
+ * @var int
+ */
+	const LC_MONETARY = 3;
+
+/**
+ * Constant for LC_NUMERIC.
+ *
+ * @var int
+ */
+	const LC_NUMERIC = 4;
+
+/**
+ * Constant for LC_TIME.
+ *
+ * @var int
+ */
+	const LC_TIME = 5;
+
+/**
+ * Constant for LC_MESSAGES.
+ *
+ * @var int
+ */
+	const LC_MESSAGES = 6;
+
 /**
  * Escape string
  *
@@ -129,7 +191,7 @@ class I18n {
  * @return string translated string.
  * @throws CakeException When '' is provided as a domain.
  */
-	public static function translate($singular, $plural = null, $domain = null, $category = 6, $count = null, $language = null) {
+	public static function translate($singular, $plural = null, $domain = null, $category = self::LC_MESSAGES, $count = null, $language = null) {
 		$_this = I18n::getInstance();
 
 		if (strpos($singular, "\r\n") !== false) {
diff --git a/lib/Cake/Test/Case/I18n/I18nTest.php b/lib/Cake/Test/Case/I18n/I18nTest.php
index 5f310b086..35ff4b056 100644
--- a/lib/Cake/Test/Case/I18n/I18nTest.php
+++ b/lib/Cake/Test/Case/I18n/I18nTest.php
@@ -1760,8 +1760,12 @@ class I18nTest extends CakeTestCase {
  */
 	public function testCategory() {
 		Configure::write('Config.language', 'po');
+		// Test with default (I18n constant) category.
 		$category = $this->_category();
 		$this->assertEquals('Monetary Po (translated)', $category);
+		// Test with category number represenation.
+		$category = $this->_category(3);
+		$this->assertEquals('Monetary Po (translated)', $category);
 	}
 
 /**
@@ -1844,11 +1848,11 @@ class I18nTest extends CakeTestCase {
 	public function testTranslateLanguageParam() {
 		Configure::write('Config.language', 'rule_0_po');
 
-		$result = I18n::translate('Plural Rule 1', null, null, 6);
+		$result = I18n::translate('Plural Rule 1', null, null, I18n::LC_MESSAGES);
 		$expected = 'Plural Rule 0 (translated)';
 		$this->assertEquals($expected, $result);
 
-		$result = I18n::translate('Plural Rule 1', null, null, 6, null, 'rule_1_po');
+		$result = I18n::translate('Plural Rule 1', null, null, I18n::LC_MESSAGES, null, 'rule_1_po');
 		$expected = 'Plural Rule 1 (translated)';
 		$this->assertEquals($expected, $result);
 	}
@@ -1926,7 +1930,7 @@ class I18nTest extends CakeTestCase {
  *
  * @return void
  */
-	protected function _category($category = 3) {
+	protected function _category($category = I18n::LC_MONETARY) {
 		$singular = __c('Plural Rule 1', $category);
 		return $singular;
 	}
diff --git a/lib/Cake/basics.php b/lib/Cake/basics.php
index 9e483ad35..a8ec196f0 100644
--- a/lib/Cake/basics.php
+++ b/lib/Cake/basics.php
@@ -585,7 +585,7 @@ if (!function_exists('__n')) {
 		}
 
 		App::uses('I18n', 'I18n');
-		$translated = I18n::translate($singular, $plural, null, 6, $count);
+		$translated = I18n::translate($singular, $plural, null, I18n::LC_MESSAGES, $count);
 		if ($args === null) {
 			return $translated;
 		} elseif (!is_array($args)) {
@@ -647,7 +647,7 @@ if (!function_exists('__dn')) {
 			return;
 		}
 		App::uses('I18n', 'I18n');
-		$translated = I18n::translate($singular, $plural, $domain, 6, $count);
+		$translated = I18n::translate($singular, $plural, $domain, I18n::LC_MESSAGES, $count);
 		if ($args === null) {
 			return $translated;
 		} elseif (!is_array($args)) {
@@ -669,15 +669,15 @@ if (!function_exists('__dc')) {
  * The category argument allows a specific category of the locale settings to be used for fetching a message.
  * Valid categories are: LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, LC_MESSAGES and LC_ALL.
  *
- * Note that the category must be specified with a numeric value, instead of the constant name. The values are:
+ * Note that the category must be specified with a class constant of I18n, instead of the constant name. The values are:
  *
- * - LC_ALL       0
- * - LC_COLLATE   1
- * - LC_CTYPE     2
- * - LC_MONETARY  3
- * - LC_NUMERIC   4
- * - LC_TIME      5
- * - LC_MESSAGES  6
+ * - LC_ALL       I18n::LC_ALL
+ * - LC_COLLATE   I18n::LC_COLLATE
+ * - LC_CTYPE     I18n::LC_CTYPE
+ * - LC_MONETARY  I18n::LC_MONETARY
+ * - LC_NUMERIC   I18n::LC_NUMERIC
+ * - LC_TIME      I18n::LC_TIME
+ * - LC_MESSAGES  I18n::LC_MESSAGES
  *
  * @param string $domain Domain
  * @param string $msg Message to translate
@@ -715,15 +715,15 @@ if (!function_exists('__dcn')) {
  * The category argument allows a specific category of the locale settings to be used for fetching a message.
  * Valid categories are: LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, LC_MESSAGES and LC_ALL.
  *
- * Note that the category must be specified with a numeric value, instead of the constant name. The values are:
+ * Note that the category must be specified with a class constant of I18n, instead of the constant name. The values are:
  *
- * - LC_ALL       0
- * - LC_COLLATE   1
- * - LC_CTYPE     2
- * - LC_MONETARY  3
- * - LC_NUMERIC   4
- * - LC_TIME      5
- * - LC_MESSAGES  6
+ * - LC_ALL       I18n::LC_ALL
+ * - LC_COLLATE   I18n::LC_COLLATE
+ * - LC_CTYPE     I18n::LC_CTYPE
+ * - LC_MONETARY  I18n::LC_MONETARY
+ * - LC_NUMERIC   I18n::LC_NUMERIC
+ * - LC_TIME      I18n::LC_TIME
+ * - LC_MESSAGES  I18n::LC_MESSAGES
  *
  * @param string $domain Domain
  * @param string $singular Singular string to translate
@@ -758,15 +758,15 @@ if (!function_exists('__c')) {
  * The category argument allows a specific category of the locale settings to be used for fetching a message.
  * Valid categories are: LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, LC_MESSAGES and LC_ALL.
  *
- * Note that the category must be specified with a numeric value, instead of the constant name. The values are:
+ * Note that the category must be specified with a class constant of I18n, instead of the constant name. The values are:
  *
- * - LC_ALL       0
- * - LC_COLLATE   1
- * - LC_CTYPE     2
- * - LC_MONETARY  3
- * - LC_NUMERIC   4
- * - LC_TIME      5
- * - LC_MESSAGES  6
+ * - LC_ALL       I18n::LC_ALL
+ * - LC_COLLATE   I18n::LC_COLLATE
+ * - LC_CTYPE     I18n::LC_CTYPE
+ * - LC_MONETARY  I18n::LC_MONETARY
+ * - LC_NUMERIC   I18n::LC_NUMERIC
+ * - LC_TIME      I18n::LC_TIME
+ * - LC_MESSAGES  I18n::LC_MESSAGES
  *
  * @param string $msg String to translate
  * @param integer $category Category