Hi
<asp:gridview runat=""server"" id=""gvDemo"" xmlns:asp="#unknown">
<columns>
<asp:templatefield>
<itemtemplate>
<%#Container.DataItemIndex+1 %>
</itemtemplate>
</asp:templatefield>
</columns>
</asp:gridview>
For Example
http://www.dotnetexpertsforum.com/how-to-add-serial-number-column-to-gridview-in-asp-net-t229.html
thnx