diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index 3c4d731a4f4..f8f4c39415a 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -170,6 +170,7 @@ it from source control: http://www.mediawiki.org/wiki/Download_from_SVN
   etc. (AKA lists) instead of arrays with pageIDs as keys (AKA hash tables)
   for consistency with other list modules.
 * Added action=watch
+* (bug 15275) apprefix and related parameters ignore spaces at the end
 
 === Languages updated in 1.14 ===
 
diff --git a/includes/api/ApiQueryBase.php b/includes/api/ApiQueryBase.php
index b1e67522f51..b5ceb75e63b 100644
--- a/includes/api/ApiQueryBase.php
+++ b/includes/api/ApiQueryBase.php
@@ -324,15 +324,7 @@ abstract class ApiQueryBase extends ApiBase {
 	 * @return string Page title with underscores
 	 */
 	public function titleToKey($title) {
-		$t = Title::newFromText($title);
-		if(!$t)
-		{
-			# Don't throw an error if we got an empty string
-			if($title == '')
-				return '';
-			$this->dieUsageMsg(array('invalidtitle', $title));
-		}
-		return $t->getDbKey();
+		return str_replace(' ', '_', $title);
 	}
 
 	/**
@@ -341,16 +333,7 @@ abstract class ApiQueryBase extends ApiBase {
 	 * @return string Page title with spaces
 	 */
 	public function keyToTitle($key) {
-		$t = Title::newFromDbKey($key);
-		# This really shouldn't happen but we gotta check anyway
-		if(!$t)
-		{
-			# Don't throw an error if we got an empty string
-			if($key == '')
-				return '';
-			$this->dieUsageMsg(array('invalidtitle', $key));
-		}
-		return $t->getPrefixedText();
+		return str_replace('_', ' ', $key);
 	}
 
 	/**