I found awnser to my query, so i thought to share it in this forum so others can also know this. Bydefault ASP.NET implements Page Controller pattern through out the ASP.NET Page life cycle which is the code-behind page. For beginners who have just started working on ASP.NET the page controller pattern can serve as entry level. The drawback is lack of unit testing and repetition of logic as the logic resides inside the code behind file. Next level after this could be the MVP pattern, which is best for UI applications like ASP.NET, Windows, Mobile, etc. This pattern is easy to learn and very manageable. But it is recommended only if you need unit testing, you need to reuse the logic, or your interface can be different like Web, Windows or Mobile application. Shabbir you can correct me if I am incorrect anywhere, Thanks.