In a review of selected literature on Health Information Systems (HIS) evaluation, a specific focus on Clinical Decision Support Systems (CDSS) is taken because of their relative popularity. This paper discusses the issues and problems of CDSS evaluation such as methods, adoption and barriers. The limited use and evaluation of CDSS are still debated. Clinical evaluations of CDSS performed in the actual clinical settings may provide better understanding of their adoption, particularly in the diagnostic function. New HIS evaluation frameworks that incorporate technological, human and organisational issues may be useful to complement existing ones.