Object oriented software development is designed to be modular, with code reuse being very common. When bugs are introduced, they can manifest themselves in one or more sections of code, but originating in a completely different area. This poster outlines the features of ImpactViz, a novel approach for visualizing class dependencies and the impact of changes in software revisions stored within a repository. Categories and Subject Descriptors D.2.5 [Software]: Software Engineering--Testing and Debugging; H.5.2 [Information Systems]: Information Interfaces and Presentation--User Interfaces General Terms Design, Human Factors