Case-based reasoning (CBR) is a problem-solving paradigm where past ex
periences are used to guide problem-solving. This paradigm shows a gre
at deal of promise for use in intelligent systems. Recent work in inte
lligent systems focusing on AIDS prevention reflects a growing interes
t in the case-based paradigm because AIDS prevention experts rely heav
ily on memory of previous cases when assessing subjects that exhibit A
IDS-risky behaviors. If an AIDS prevention expert has seen a subject w
ith similar AIDS-risky behavior previously, he or she is likely to dra
w on that experience to propose a solution to the new case at hand. Th
is paper describes a CBR system that functions as an AIDS prevention e
xpert. The inputs are risk behavior descriptions and the subject's tes
t results. The system employs fuzzy mathematical algorithms to retriev
e and select previous cases, thereby assessing the subject's risk.