Modified programs are required to be retested to determine whether changes have been made correctly and to investigate whether those cause any adverse effect on the program behavior. Then, the key issue is the extent of the retesting tasks. To save time and efforts, retesting should be done on only the parts that might be affected by changes. Change impact analysis is the activity which identifies the parts to be retested.Object-oriented paradigm is based on several concepts such as encapsulation, inheritance, polymorphism, and dynamic binding. Although these features contribute to the reusability and extensibility of systems, they produce complex dependencies between classes and attributes, which make it difficult to identify the affected components by changes.We propose an approach for analyzing change impact in a class hierarchy. Our approach is based on the class firewall method, but aims to reduce the retesting effort significantly by taking a member function as a test unit. We deal with the impacts of changes associated with various object-oriented features as well as types of changes which can occur at the level of a data member, a member function, a class, and an inheritance relation.