Evaluation is an essential process that permits assessing the effectiveness and efficiency of planned programs. In implementing a new nurse-managed Community Health Clinic targeting services for the homeless and underserved, the stakeholders considered an evaluation process integral to the planning stage of the clinic as a whole as well as of all the different programs being offered. The program logic model was chosen and modified to guide evaluation. Work to develop the evaluation model and its components began before the clinic opened. This article describes the development of the modified program logic model, how it was modified, and the rationale for its modifications. We highlight the process of developing the evaluation model because we found limited descriptions of the process in the literature. The evaluation process itself will be evaluated on an ongoing basis to determine if it is capturing the evaluation needs of the clinic project accurately.