diff --git a/MysqliDb.php b/MysqliDb.php
index 42dc34a8..ff4832d3 100644
--- a/MysqliDb.php
+++ b/MysqliDb.php
@@ -112,6 +112,18 @@ class MysqliDb
      */
     protected $isSubQuery = false;
 
+    /**
+     * Name of the auto increment column 
+     *
+     */
+    protected $_lastInsertId = null;
+
+    /**
+     * Column names for update when using onDuplicate method
+     *
+     */
+    protected $_updateColumns = null;
+
     /**
      * Return type: 'Array' to return results as array, 'Object' as object
      * 'Json' as json string
@@ -235,6 +247,8 @@ protected function reset()
         $this->returnType = 'Array';
         $this->_nestJoin = false;
         $this->_tableName = '';
+        $this->_lastInsertId = null;
+        $this->_updateColumns = null;
     }
 
     /**
@@ -550,6 +564,19 @@ public function where($whereProp, $whereValue = 'DBNULL', $operator = '=', $cond
         return $this;
     }
 
+    /** 
+     * This function store update column's name and column name of the 
+     * autoincrement column
+     * 
+     * @param Array Variable with values
+     * @param String Variable value 
+     */
+    public function onDuplicate($_updateColumns, $_lastInsertId = null)
+    {
+        $this->_lastInsertId = $_lastInsertId;
+        $this->_updateColumns = $_updateColumns;
+    }
+
     /**
      * This method allows you to specify multiple (method chaining optional) OR WHERE statements for SQL queries.
      *
@@ -779,6 +806,57 @@ private function _buildInsert ($tableName, $insertData, $operation)
         return true;
     }
 
+    /** 
+     * Helper function to add variables into the query statement
+     * 
+     * @param Array Variable with values
+     */
+    protected function _buildDuplicate($tableData)
+    {
+        if (is_array($this->_updateColumns) && !empty($this->_updateColumns)) {
+            $this->_query .= " on duplicate key update ";
+            if ($this->_lastInsertId) {
+                $this->_lastQuery .= $this->_lastInsertId."=LAST_INSERT_ID(".$this->_lastInsertId."),";
+                $this->_lastInsertId = null;
+            }
+            
+            foreach ($this->_updateColumns as $column) {
+                $this->_query .= "`" . $column . "` = ";
+                
+                // Simple value
+                if (!is_array ($tableData[$column])) {
+                    $this->_bindParam($tableData[$column]);
+                    $this->_query .= '?, ';
+                    continue;
+                }
+                
+                // Function value
+                $arr = $tableData[$column];
+                $key = key($arr);
+                $val = $arr[$key];
+                switch ($key) {
+                case '[I]':
+                    $this->_query .= $column . $val . ", ";
+                    break;
+                case '[F]':
+                    $this->_query .= $val[0] . ", ";
+                    if (!empty ($val[1]))
+                        $this->_bindParams ($val[1]);
+                    break;
+                case '[N]':
+                    if ($val == null)
+                        $this->_query .= "!" . $column . ", ";
+                    else
+                        $this->_query .= "!" . $val . ", ";
+                    break;
+                default:
+                    die ("Wrong operation");
+                }
+            }
+            $this->_query = rtrim($this->_query, ', ');
+        }
+    }
+
     /**
      * Abstraction method that will compile the WHERE statement,
      * any passed update data, and the desired rows.
@@ -798,6 +876,7 @@ protected function _buildQuery($numRows = null, $tableData = null)
         $this->_buildGroupBy();
         $this->_buildOrderBy();
         $this->_buildLimit ($numRows);
+        $this->_buildDuplicate($tableData);
 
         $this->_lastQuery = $this->replacePlaceHolders ($this->_query, $this->_bindParams);
 
diff --git a/readme.md b/readme.md
index dfd9a9de..299f2f3c 100644
--- a/readme.md
+++ b/readme.md
@@ -123,6 +123,20 @@ else
     echo 'insert failed: ' . $db->getLastError();
 ```
 
+Insert with on duplicate key update
+```php
+$data = Array ("login" => "admin",
+               "firstName" => "John",
+               "lastName" => 'Doe',
+               "createdAt" => $db->now(),
+               "updatedAt" => $db->now(),
+);
+$updateColumns = Array ("updateAt");
+$lastInsertId = "id";
+$db->onDuplicate($updateColumns, $lastInsertId);
+$id = $db->insert ('users', $data);
+```
+
 ### Replace Query
 <a href='https://dev.mysql.com/doc/refman/5.0/en/replace.html'>Replace()</a> method implements same API as insert();
 
diff --git a/tests/mysqliDbTests.php b/tests/mysqliDbTests.php
index 0cdcd34e..6a83b668 100644
--- a/tests/mysqliDbTests.php
+++ b/tests/mysqliDbTests.php
@@ -29,8 +29,10 @@
         'lastName' => 'char(10)',
         'password' => 'text not null',
         'createdAt' => 'datetime',
+        'updatedAt' => 'datetime',
         'expires' => 'datetime',
-        'loginCount' => 'int(10) default 0'
+        'loginCount' => 'int(10) default 0',
+        'unique key' => 'login (login)'
     ),
     'products' => Array (
         'customerId' => 'int(10) not null',
@@ -46,6 +48,7 @@
                'lastName' => 'Doe',
                'password' => $db->func('SHA1(?)',Array ("secretpassword+salt")),
                'createdAt' => $db->now(),
+               'updatedAt' => $db->now(),
                'expires' => $db->now('+1Y'),
                'loginCount' => $db->inc()
         ),
@@ -55,6 +58,7 @@
                'lastName' => NULL,
                'password' => $db->func('SHA1(?)',Array ("secretpassword2+salt")),
                'createdAt' => $db->now(),
+               'updatedAt' => $db->now(),
                'expires' => $db->now('+1Y'),
                'loginCount' => $db->inc(2)
         ),
@@ -65,6 +69,7 @@
                'lastName' => 'D',
                'password' => $db->func('SHA1(?)',Array ("secretpassword2+salt")),
                'createdAt' => $db->now(),
+               'updatedAt' => $db->now(),
                'expires' => $db->now('+1Y'),
                'loginCount' => $db->inc(3)
         )
@@ -136,6 +141,7 @@ function createTable ($name, $data) {
                'lastName' => 'Doe',
                'password' => 'test',
                'createdAt' => $db->now(),
+               'updatedAt' => $db->now(),
                'expires' => $db->now('+1Y'),
                'loginCount' => $db->inc()
         );
@@ -170,6 +176,23 @@ function createTable ($name, $data) {
     exit;
 }
 
+// insert with on duplicate key update
+$user = Array ('login' => 'user3',
+       'active' => true,
+       'customerId' => 11,
+       'firstName' => 'Pete',
+       'lastName' => 'D',
+       'password' => $db->func('SHA1(?)',Array ("secretpassword2+salt")),
+       'createdAt' => $db->now(),
+       'updatedAt' => $db->now(),
+       'expires' => $db->now('+1Y'),
+       'loginCount' => $db->inc(3)
+       );
+$updateColumns = Array ("updatedAt");
+$insertLastId = "id";
+$db->onDuplicate($updateColumns, "id");
+$db->insert("users", $user);
+
 // order by field
 $db->orderBy("login","asc", Array ("user3","user2","user1"));
 $login = $db->getValue ("users", "login");