The rapid growth of the homeless population in North America has given rise to a sharp increase in the number of task forces and studies aimed at setting up either programs for the homeless, or policies for controlling the phenomenon. Whenever there is a need for program evaluations in this process, numerous methodological and strategic challenges have to be faced. Due to the characteristics of the clientele, evaluation studies of services for the homeless call for innovative approaches. This paper reviews the research strategies (types of evaluations, designs, and indicators) that have been developed to assess programs for chronic inebriates and mentally ill homeless. The findings from previous evaluations are then summarized and their consequences for evaluation practice are considered.