Fidelity measurement is an evolving field in mental health case management program evaluation. This article presents an exploratory study in which two separate fidelity measures, the Dartmouth Assertive Community Treatment Scale (DACTS) and the Key Component Profiles (KCP), were used to assess structure and process elements of three mental health case management programs. The programs were studied because they all provided services to seriously mentally ill inner city populations and shared a common context for practice. However, one program followed the Assertive Community Treatment (ACT) model, the other two were Intensive Case Management (ICM) programs, and one of the ICM programs formed a significant partnership with a home care agency for service delivery. The extent to which the DACTS and KCP were able to measure the structure and process similarities and differences of the programs is examined. The results provide information for evaluators on the possible strengths and limitations of each fidelity tool in differentiating various elements of the case management models and reinforce the importance of assessing program fidelity from a multi-dimensional perspective.