diff --git a/system/language/english/form_validation_lang.php b/system/language/english/form_validation_lang.php
index 9156ebe..e44a9e2 100644
--- a/system/language/english/form_validation_lang.php
+++ b/system/language/english/form_validation_lang.php
@@ -53,6 +53,7 @@
 $lang['form_validation_less_than_equal_to']	= 'The {field} field must contain a number less than or equal to {param}.';
 $lang['form_validation_greater_than']		= 'The {field} field must contain a number greater than {param}.';
 $lang['form_validation_greater_than_equal_to']	= 'The {field} field must contain a number greater than or equal to {param}.';
+$lang['form_validation_in']		= 'The {field} field must be within a predetermined list: {param}.';
 
 /* End of file form_validation_lang.php */
 /* Location: ./system/language/english/form_validation_lang.php */
\ No newline at end of file
diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index b640f1e..f3c8826 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -1438,6 +1438,22 @@
 	// --------------------------------------------------------------------
 
 	/**
+	 * Value should be within an array of values
+	 *
+	 * @param	string
+	 * @param	array
+	 * @return	bool
+	 */
+	public function in($value, $list)
+	{
+		$list = array_map('trim', explode(',', (string) $list));
+
+		return in_array((string) $value, $list);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Is a Natural number  (0,1,2,3, etc.)
 	 *
 	 * @param	string