Would I be entitled to any part of my estranged parent''s estate when they pass away. I have had no contact with that parent in more than 40 years.

From your question, it sounds as though you are only referring to one parent and that that parent is still alive AND is currently married to his/her second spouse.  I will base my response on this assumption.  Your answer depends on whether or not your parent dies leaving a will and how the assets in their estate are titled.  Please note that I am an attorney in the state of Illinois so please contact an attorney in PA for the specific laws of your home state. If your parent dies (called a decedent) leaving a will, the terms of the will will govern.  Your parent may have left you an inheritance in the will or he or she may not have.  It is totally legal for a parent to intentionally disinherit an adult child.  If your parent dies intestate, meaning without a will, but DOES have a surviving spouse, then one half of his or her entire  estate will go to the surviving spouse and the other half to the descendants of the decedent.  You advise there are no other living children, but note that if the deceased children (if any) left children (your parent's grandchildren), these children would take by representation the share entitled to their parents.  You would actually benefit if your parent dies without a will assuming they left an estate.  Your estrangement would not factor in.  However, even if your parent dies intestate, they may have titled their assets in such a way to pass them on to intended beneficiaries and thereby exclude you from his/her estate. I hope that helps.