 <p>Maybe you can try it like this: </p> <pre><code>com1.CommandText = "TRB01.set_idoc('DOC','1','" + sender + "','" + reciver + "'," + "to_timestamp_tz('"+ cre_date + "','yyyy-mm-dd\"T\"hh24:mi:ss:TZH:TZM'),'" + bod_ID + "')"; com1.ExecuteNonQuery(); </code></pre> <p>Though a better solution should be by havaing a <code>DateTime</code> in c# code and adding it as an OracleParameter</p>