How to Increase a Date?

How can I add 1 day to a Date. I've tried this: MyDate.Add(new TimeSpan(1,0,0,0)) but it doesn't work. I'm using it into a while statement, like this: MyDate = DateTime.Now; FinalDate = dtpFinalDate.Value; while (MyDate <= FinalDate) { //Statement MyDate.Add(new TimeSpan(1,0,0,0)) } what am I doing wrong? thanx in advance.