diff --git a/src/Jfelder/OracleDB/OCI_PDO/OCIStatement.php b/src/Jfelder/OracleDB/OCI_PDO/OCIStatement.php
index 6aea247..238350c 100644
--- a/src/Jfelder/OracleDB/OCI_PDO/OCIStatement.php
+++ b/src/Jfelder/OracleDB/OCI_PDO/OCIStatement.php
@@ -34,7 +34,8 @@ class OCIStatement extends \PDOStatement
      */
     protected $datatypes = [
         \PDO::PARAM_BOOL => \SQLT_INT,
-        \PDO::PARAM_NULL => \SQLT_INT,
+        // there is no SQLT_NULL, but oracle will insert a null value if it receives an empty string
+        \PDO::PARAM_NULL => \SQLT_CHR,
         \PDO::PARAM_INT => \SQLT_INT,
         \PDO::PARAM_STR => \SQLT_CHR,
         \PDO::PARAM_INPUT_OUTPUT => \SQLT_CHR,
diff --git a/tests/OracleDBOCIStatementTest.php b/tests/OracleDBOCIStatementTest.php
index 749785f..742a2ed 100644
--- a/tests/OracleDBOCIStatementTest.php
+++ b/tests/OracleDBOCIStatementTest.php
@@ -181,6 +181,13 @@ public function testBindValueWithValidDataType()
         $this->assertTrue($this->stmt->bindValue('param', 'hello'));
     }
 
+    public function testBindValueWithNullDataType()
+    {
+        global $OCIBindByNameTypeReceived;
+        $this->assertTrue($this->stmt->bindValue('param', null, \PDO::PARAM_NULL));
+        $this->assertSame(\SQLT_CHR, $OCIBindByNameTypeReceived);
+    }        
+
     /**
      * @expectedException \InvalidArgumentException
      */
diff --git a/tests/mocks/OCIFunctions.php b/tests/mocks/OCIFunctions.php
index c956a2f..f41166f 100644
--- a/tests/mocks/OCIFunctions.php
+++ b/tests/mocks/OCIFunctions.php
@@ -7,6 +7,7 @@
     $OCIExecuteStatus = true;
     $OCIFetchStatus = true;
     $OCIBindChangeStatus = false;
+    $OCIBindByNameTypeReceived = null;
 }
 
 namespace Jfelder\OracleDB\OCI_PDO {
@@ -79,7 +80,10 @@ function get_resource_type($a = '')
     if (! function_exists("Jfelder\OracleDB\OCI_PDO\oci_bind_by_name")) {
         function oci_bind_by_name($a = '', $b = '', &$c, $d = '', $e = '')
         {
-            global $OCIStatementStatus, $OCIBindChangeStatus;
+            global $OCIStatementStatus, $OCIBindChangeStatus, $OCIBindByNameTypeReceived;
+
+            $OCIBindByNameTypeReceived = $e;
+            
             if ($OCIBindChangeStatus) {
                 $c = 'oci_bind_by_name';
             }