we were able to keep our old foam mattress. works great, we have had a straight bed forever. myself i've had a really bad back for the last 22 years, unable to lay on my back for about 15 of those yrs. got out new adjustable bed base, boy it sure feels good being able to slepp on my back. my feet in the air and my head about the same height. what a way to go love it... GREAT BUY.....