Phoebe Abbott Sr. is Phoebe Buffay's birth mother. She is first introduced when Phoebe Buffay finds out that this woman knew her parents. So Phoebe Buffay, Chandler Bing, Joey Tribbiani, Ross Geller, Monica Geller and Rachel Green head to a beach house to stay while Phoebe Buffay visits who she thinks is a friend of her mum's. When Phoebe Buffay visits Phoebe Abbott Sr, she starts questioning her about her parents and what they were like. Phoebe Abbott Sr. lies to Phoebe Buffay but she soon realises she's lying. When the truth comes out that Phoebe Abbott Sr. is in fact Phoebe Buffay's birth mother, the two Phoebe's build up a relationship.Phoebe Abbott Sr's. last appearance is when Phoebe Buffay is having trouble deciding whether or not to be a surrogate for her brother Frank Jr. and his wife Alice. Phoebe Abbott Sr. loans her daughter a puppy to look after and see how hard it is to give up the puppy. This does not go to plan and Phoebe Buffay ends up giving the puppy to Frank Jr. and Alice. She then agrees to be the surrogate because she saw how happy the puppy made Frank Jr. and Alice.