We describe here the latest observations on poly(ADP-ribose) glycohydrolase. There is now extensive evidence that this nuclear enzyme is an endo-exoglycosidase which has a key role to perform in the removal of polymers which interact with proteins through covalent and non-covalent interactions. Also, we have developed a zymogram which will permit the isolation of the various isoforms of the glycohydrolase and the eventual cloning of this enzyme. Finally, we have evidence that very short oligomers and even monomers of ADP-ribose covalently bound to proteins can be removed by poly(ADP-ribose) glycohydrolase.