diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index c602cfdcd2..12801b1fc8 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -53,6 +53,7 @@
 <ol>
 	<li><a href="#changelog">Changelog</a>
 	<ol style="list-style-type: lower-roman;">
+		<li><a href="#v300">Changes since 3.0.0</a></li>
 		<li><a href="#v30rc8">Changes since RC-8</a></li>
 		<li><a href="#v30rc7">Changes since RC-7</a></li>
 		<li><a href="#v30rc6">Changes since RC-6</a></li>
@@ -70,7 +71,7 @@
 
 		<span class="corners-bottom"><span></span></span></div>
 	</div>
-
+	
 	<hr />
 
 	<a name="changelog"></a><h2>1. Changelog</h2>
@@ -80,6 +81,12 @@
 
 		<div class="content">
 
+	<a name="v300"></a><h3>1.i. Changes since 3.0.0</h3>
+
+	<ul>
+		<li>[Change] Validate birthdays (Bug #15004)</li>
+	</ul>
+	
 	<a name="v30rc8"></a><h3>1.i. Changes since 3.0.RC8</h3>
 
 	<ul>
diff --git a/phpBB/includes/acp/acp_users.php b/phpBB/includes/acp/acp_users.php
index 260acbbc52..310759d38c 100644
--- a/phpBB/includes/acp/acp_users.php
+++ b/phpBB/includes/acp/acp_users.php
@@ -1060,9 +1060,11 @@ class acp_users
 					list($data['bday_day'], $data['bday_month'], $data['bday_year']) = explode('-', $user_row['user_birthday']);
 				}
 
-				$data['bday_day'] = request_var('bday_day', $data['bday_day']);
-				$data['bday_month'] = request_var('bday_month', $data['bday_month']);
-				$data['bday_year'] = request_var('bday_year', $data['bday_year']);
+				$data['bday_day']		= request_var('bday_day', $data['bday_day']);
+				$data['bday_month']		= request_var('bday_month', $data['bday_month']);
+				$data['bday_year']		= request_var('bday_year', $data['bday_year']);
+				$data['user_birthday']	= sprintf('%2d-%2d-%4d', $data['bday_day'], $data['bday_month'], $data['bday_year']);
+
 
 				if ($submit)
 				{
@@ -1085,6 +1087,7 @@ class acp_users
 						'bday_day'		=> array('num', true, 1, 31),
 						'bday_month'	=> array('num', true, 1, 12),
 						'bday_year'		=> array('num', true, 1901, gmdate('Y', time())),
+						'user_birthday'	=> array('date', true),
 					));
 
 					// validate custom profile fields
@@ -1111,7 +1114,7 @@ class acp_users
 							'user_from'		=> $data['location'],
 							'user_occ'		=> $data['occupation'],
 							'user_interests'=> $data['interests'],
-							'user_birthday'	=> sprintf('%2d-%2d-%4d', $data['bday_day'], $data['bday_month'], $data['bday_year']),
+							'user_birthday'	=> $data['user_birthday'],
 						);
 
 						$sql = 'UPDATE ' . USERS_TABLE . '
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index fa7025f2c2..c9921cc6f0 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1260,6 +1260,45 @@ function validate_num($num, $optional = false, $min = 0, $max = 1E99)
 	return false;
 }
 
+/**
+* Validate Date
+* @param String $string a date in the dd-mm-yyyy format
+* @return	boolean
+*/
+function validate_date($date_string, $optional = false)
+{
+	$date = explode('-', $date_string);
+	if ((empty($date) || sizeof($date) != 3) && $optional)
+	{
+		return false;
+	}
+	else if ($optional)
+	{
+		for ($field = 0; $field <= 1; $field++)
+		{
+			$date[$field] = (int) $date[$field];
+			if (empty($date[$field]))
+			{
+				$date[$field] = 1;
+			}
+		}
+		$date[2] = (int) $date[2];
+		// assume an arbitrary leap year
+		if (empty($date[2]))
+		{
+			$date[2] = 1980;
+		}
+	}
+	
+	if (sizeof($date) != 3 || !checkdate($date[1], $date[0], $date[2]))
+	{
+		return 'INVALID';
+	}
+
+	return false;
+}
+
+
 /**
 * Validate Match
 *
diff --git a/phpBB/includes/ucp/ucp_profile.php b/phpBB/includes/ucp/ucp_profile.php
index 3fe3d72d59..0f3cc218c3 100644
--- a/phpBB/includes/ucp/ucp_profile.php
+++ b/phpBB/includes/ucp/ucp_profile.php
@@ -295,6 +295,7 @@ class ucp_profile
 					$data['bday_day'] = request_var('bday_day', $data['bday_day']);
 					$data['bday_month'] = request_var('bday_month', $data['bday_month']);
 					$data['bday_year'] = request_var('bday_year', $data['bday_year']);
+					$data['user_birthday'] = sprintf('%2d-%2d-%4d', $data['bday_day'], $data['bday_month'], $data['bday_year']);
 				}
 
 				add_form_key('ucp_profile_info');
@@ -325,6 +326,7 @@ class ucp_profile
 							'bday_day'		=> array('num', true, 1, 31),
 							'bday_month'	=> array('num', true, 1, 12),
 							'bday_year'		=> array('num', true, 1901, gmdate('Y', time()) + 50),
+							'user_birthday' => array('date', true),
 						));
 					}
 
@@ -359,7 +361,7 @@ class ucp_profile
 
 						if ($config['allow_birthdays'])
 						{
-							$sql_ary['user_birthday'] = sprintf('%2d-%2d-%4d', $data['bday_day'], $data['bday_month'], $data['bday_year']);
+							$sql_ary['user_birthday'] = $data['user_birthday'];
 						}
 
 						$sql = 'UPDATE ' . USERS_TABLE . '
diff --git a/phpBB/language/en/ucp.php b/phpBB/language/en/ucp.php
index 0a553b9366..d7006549ce 100644
--- a/phpBB/language/en/ucp.php
+++ b/phpBB/language/en/ucp.php
@@ -223,6 +223,7 @@ $lang = array_merge($lang, array(
 
 	'IF_FOLDER_FULL'			=> 'If folder is full',
 	'IMPORTANT_NEWS'			=> 'Important announcements',
+	'INVALID_USER_BIRTHDAY'			=> 'The entered birthday is not a valid date.',
 	'INVALID_CHARS_USERNAME'	=> 'The username contains forbidden characters.',
 	'INVALID_CHARS_NEW_PASSWORD'=> 'The password does not contain the required characters.',
 	'ITEMS_REQUIRED'			=> 'The items marked with * are required profile fields and need to be filled out.',