System.DateTime dateFirstOfMonth = new System.DateTime(System.DateTime.Now.Year, System.DateTime.Now.Month, 1, 0, 0, 0); System.TimeSpan oneDay = new System.TimeSpan(1, 0, 0, 0, 0); System.DateTime dateLastOfMonth = dateFirstOfMonth.Subtract(oneDay);You'll have to adjust it for the first of the current month, but hopefully the code gives you an idea on how. There might be other ways...