I am installing a full bath room in basement I need to tie into the ol pipe ad trsition to pvc

What material is the old pipe made of? What is the inside diameter of the old pipe? How will this bathroom be vented?
Back to you , Tom

In addition to Tom's questions, I'll add, PVC?? I would not use PVC but CPVC.

My guess here is we are talking about a DRAIN line. If that is the case, the drain is either cast iron, PVC or ABS pipe. Once we know the pipe type we can tell you the proper transition clamp, OK?

Back to you...

Mark