add java script function filterGrid(ddl) { if (ddl.value == '*') { Grid1.removeFilter(); } else { Grid1.addFilterCriteria('AccountRep', OboutGridFilterCriteria.EqualTo, ddl.value); Grid1.executeFilter(); } } set grid to AllowFiltering="True" and FilterType="ProgrammaticOnly" if (!Page.IsPostBack) { ddlReps.Attributes["onchange"] = "filterGrid(this)"; }