diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 44e93a0..dd803ab 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -509,33 +509,19 @@
 
 	/**
 	 * Insert ID
-	 * 
-	 * @access	public
-	 * @return	integer
+	 *
+	 * @return	int
 	 */
-	function insert_id($name=NULL)
+	public function insert_id($name = NULL)
 	{
-		if ($this->pdodriver == 'pgsql')
+		if ($this->pdodriver === 'pgsql' && $name === NULL && $this->_version() >= '8.1')
 		{
-			//Convenience method for postgres insertid
-			$v = $this->_version();
-
-			$table	= func_num_args() > 0 ? func_get_arg(0) : NULL;
-
-			if ($table == NULL && $v >= '8.1')
-			{
-				$sql='SELECT LASTVAL() as ins_id';
-			}
-
-			$query = $this->query($sql);
-			$row   = $query->row();
-
-			return $row->ins_id;
+			$query = $this->query('SELECT LASTVAL() AS ins_id');
+			$query = $query->row();
+			return $query->ins_id;
 		}
-		else
-		{
-			return $this->conn_id->lastInsertId($name);
-		}
+
+		return $this->conn_id->lastInsertId($name);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index b1bef0c..3d3c158 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -119,6 +119,7 @@
 -  Fixed a bug (#611) - SQLSRV's _error_message() and _error_number() methods used to issue warnings when there's no actual error.
 -  Fixed a bug (#1036) - is_write_type() method in the :doc:`Database Library <database/index>` didn't return TRUE for RENAME and OPTIMIZE queries.
 -  Fixed a bug in PDO's _version() method where it used to return the client version as opposed to the server one.
+-  Fixed a bug in PDO's insert_id() method where it could've failed if it's used with Postgre versions prior to 8.1.
 
 Version 2.1.1
 =============