Decades of research on maintenance activities in the procedural paradigm has produced several conclusions. Among these conclusions are recommendations that a reduction in maintenance cost could be achieved by a more controlled design process, by more rigorous testing of potential problem areas earlier in the life cycle. With the increasing emphasis on the object oriented paradigm, the authors performed an empirical study of the maintenance patterns in two commercial object oriented systems. Although this is a preliminary study, intuition is presented as insight into the object oriented maintenance activities