Is Valid: Validate which also validate normal required fields etc...I do want the validation and message all in the user control.I found the validation controls provided by are applicable to the built in server controls. I am not able to attach these validation controls with my custom control. If i am using Text Box control then the Required Field Validator is applicable to it. Also note that in my current setup the server side validation works fine.I understand your points but prefer to approach the problem from the other way, namely adapting the custom control in such way that the Compare Validator works with it.Interesting to say, the username is created as a combination of a dropdownlist and a textbox.;) The idea is to have below it some red text explaining that the user is not found in the db, and so nothing can be done until a correct user is entered.