The purpose of this article is to develop guidelines to assist practitioners and researchers in evaluating and developing rigorous case studies. The main concern in evaluating a case study is to accurately assess its quality and ultimately to offer clients social work interventions informed by the best available evidence. To assess the quality of a case study, we propose criteria, including transferability/external validity, credibility/internal validity, confirmability/construct validity, and dependability/reliability. Guidelines are presented in a phase-oriented framework: research design, data collection, and data analysis. Finally, several dimensions to enhance the quality at each phase of the guidelines in evaluating the case study are discussed.