The following case is reported not because it is uncommon, but rather because cases like it will become more common as the AIDS endemic in sub-Saharan Africa progresses. This is a case of a young woman previously undiagnosed as being HIV positive who was admitted to a psychiatric unit. She clinically presented with a manic episode. The case is remarkable in that it demonstrates the complicated differential diagnosis that needs to be considered in evaluating immune-compromised patients who present primarily with disturbances of mood, cognition, or behaviour.