Case study has been criticized far its lack of generalization to the larger population and lack of sampling controls. Some of shortcomings of case study methods may be overcome, by using logically consistent, rigorous, and systematic approaches. Especially, Case study method has been suggested as appropriate for researching a range of GIS implementation, utilization, and diffusion issues. This paper provides examples of how the substance of its requirements may be met in the context of GIS case study. For the successful implementation of GIS, this study suggest that the case study method in GIS appropriate to the study of casual relations in and explication of complex GIS acquisition and adoption process.