In the current market there is a proliferation of knowledge management software solutions. The aim of this paper is to discuss issues concerned in selecting such a system to support knowledge workers. Soft Systems Methodology (SSM) and SISTeM (Cycle 1) were used as problem solving approaches within an action research framework to analyse KMS issues, human computer interaction, and developing criteria for selecting a system. Selection criteria for knowledge management systems are then outlined and applied to a case study in evidence based health care.