diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index 0a6a2af..2ee734a 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -703,11 +703,11 @@
 	 *
 	 * @param	string	the field name
 	 * @param	string
-	 * @return	void
+	 * @return	string
 	 */
 	public function set_value($field = '', $default = '')
 	{
-		if ( ! isset($this->_field_data[$field]))
+		if ( ! isset($this->_field_data[$field], $this->_field_data[$field]['postdata']))
 		{
 			return $default;
 		}
@@ -736,13 +736,9 @@
 	 */
 	public function set_select($field = '', $value = '', $default = FALSE)
 	{
-		if ( ! isset($this->_field_data[$field]) OR ! isset($this->_field_data[$field]['postdata']))
+		if ( ! isset($this->_field_data[$field], $this->_field_data[$field]['postdata']))
 		{
-			if ($default === TRUE AND count($this->_field_data) === 0)
-			{
-				return ' selected="selected"';
-			}
-			return '';
+			return ($default === TRUE && count($this->_field_data) === 0) ? ' selected="selected"' : '';
 		}
 
 		$field = $this->_field_data[$field]['postdata'];
@@ -754,12 +750,9 @@
 				return '';
 			}
 		}
-		else
+		elseif (($field == '' OR $value == '') OR ($field != $value))
 		{
-			if (($field == '' OR $value == '') OR ($field != $value))
-			{
-				return '';
-			}
+			return '';
 		}
 
 		return ' selected="selected"';
@@ -779,13 +772,9 @@
 	 */
 	public function set_radio($field = '', $value = '', $default = FALSE)
 	{
-		if ( ! isset($this->_field_data[$field]) OR ! isset($this->_field_data[$field]['postdata']))
+		if ( ! isset($this->_field_data[$field], $this->_field_data[$field]['postdata']))
 		{
-			if ($default === TRUE AND count($this->_field_data) === 0)
-			{
-				return ' checked="checked"';
-			}
-			return '';
+			return ($default === TRUE && count($this->_field_data) === 0) ? ' checked="checked"' : '';
 		}
 
 		$field = $this->_field_data[$field]['postdata'];
@@ -869,9 +858,7 @@
 			return FALSE;
 		}
 
-		$field = $_POST[$field];
-
-		return ($str === $field);
+		return ($str === $_POST[$field]);
 	}
 
 	// --------------------------------------------------------------------
@@ -908,7 +895,7 @@
 	 */
 	public function min_length($str, $val)
 	{
-		if (preg_match("/[^0-9]/", $val))
+		if (preg_match('/[^0-9]/', $val))
 		{
 			return FALSE;
 		}
@@ -932,7 +919,7 @@
 	 */
 	public function max_length($str, $val)
 	{
-		if (preg_match("/[^0-9]/", $val))
+		if (preg_match('/[^0-9]/', $val))
 		{
 			return FALSE;
 		}
@@ -956,7 +943,7 @@
 	 */
 	public function exact_length($str, $val)
 	{
-		if (preg_match("/[^0-9]/", $val))
+		if (preg_match('/[^0-9]/', $val))
 		{
 			return FALSE;
 		}
@@ -1170,7 +1157,7 @@
 	 */
 	public function is_natural_no_zero($str)
 	{
-		return ($str != 0 AND preg_match('/^[0-9]+$/', $str));
+		return ($str != 0 && preg_match('/^[0-9]+$/', $str));
 	}
 
 	// --------------------------------------------------------------------
@@ -1217,7 +1204,7 @@
 			return $data;
 		}
 
-		return str_replace(array("'", '"', '<', '>'), array("&#39;", "&quot;", '&lt;', '&gt;'), stripslashes($data));
+		return str_replace(array("'", '"', '<', '>'), array('&#39;', '&quot;', '&lt;', '&gt;'), stripslashes($data));
 	}
 
 	// --------------------------------------------------------------------
@@ -1283,7 +1270,6 @@
 	}
 
 }
-// END Form Validation Class
 
 /* End of file Form_validation.php */
 /* Location: ./system/libraries/Form_validation.php */
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index cd82c01..711f825 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -109,6 +109,7 @@
 -  Fixed a possible bug in ``CI_Input::is_ajax_request()`` where some clients might not send the X-Requested-With HTTP header value exactly as 'XmlHttpRequest'.
 -  Fixed a bug (#1039) - MySQL's _backup() method failed due to a table name not being escaped.
 -  Fixed a bug (#1070) - CI_DB_driver::initialize() didn't set a character set if a database is not selected.
+-  Fixed a bug (#177) - CI_Form_validation::set_value() didn't set the default value if POST data is NULL.
 
 Version 2.1.0
 =============