Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 29738)
+++ wp-includes/taxonomy.php	(working copy)
@@ -1804,8 +1804,13 @@
 	}
 
 	if ( ! empty( $args['slug'] ) ) {
-		$slug = sanitize_title( $args['slug'] );
-		$where .= " AND t.slug = '$slug'";
+		if ( is_array( $args['slug'] ) ) {
+			$slug = array_map( 'sanitize_title', $args['slug'] );
+			$where .= " AND t.slug IN ('" . implode( "', '". $slug ) . "')";
+		} else {
+			$slug = sanitize_title( $args['slug'] );
+			$where .= " AND t.slug = '$slug'";
+		}
 	}
 
 	if ( ! empty( $args['name__like'] ) ) {