The one component of collection development most difficult for librarians is the evaluation of the collection. Various methods can be employed to evaluate the collection including statistical analysis, list checking, user opinions, direct observation, and applying standards. All of these methods have strengths and weaknesses, and numerous opinions exist on the value of each method. However, almost all experts agree that libraries need to invest a great deal of time, staff, and budget for any evaluation to be considered valuable. The process becomes even more complex when evaluating interdisciplinary areas such as women's studies. Collection development issues for women's studies has been well covered in the literature, but very little exists on the evaluation of women's studies collections. This article will discuss one method for collection evaluation, the Research Libraries Group (RLG) Conspectus, and outline the process of using the Conspectus to evaluate the women's studies collection at the Pennsylvania State University Libraries. Given the importance of information needs for diversity materials and the number of librarians who select women's studies materials among their many other responsibilities, this information will be valuable for all librarians engaged in interdisciplinary collection development in both public and academic libraries.