Aspect Oriented Software Development (AOSD) is a promising methodology which provides powerful techniques to improve the modularity of the software by separating the cross-cutting concerns from the core functionality. Since evolution is a major requirement for the sustainability of any software, it is necessary to quantitatively measure its impact. In order to quantify, it is essential to define metrics that will capture the evolution of Aspect Oriented (AO) software. It is also necessary to compare the metric values of various versions of software to draw inferences on the evolution dynamics of AO software. This needs identification of artifacts that were added, deleted or modified across versions and study the consequence of these types of changes. This paper defines a new set of metrics for measuring the evolution of Aspect Oriented software. As a case study, an aspect refactored software, AJHotDraw has been chosen and its four versions have been analyzed for their capability to evolve over time.