This prospective 2-year study examines suicidal ideation in 86 HIV-positive and 167 HIV-negative caregiving partners of men with AIDS. One hundred and fifty-six of the caregivers became bereaved during the course of the study. The study focuses on the relationship between suicidal ideation and bereavement status (bereaved vs non-bereaved), HIV serostatus (HIV-positive vs HIV-negative), and psycho-social factors (caregiving burdens, social support, coping, and optimism). Bereavement was related to suicidal ideation, but HIV serostatus was not. High suicidal ideators were characterized by feeling burdened by caregiving, perceiving low levels of social support and subjective social integration, and the use of behavioural escape-avoidance coping. Those who reported never having suicidal ideation were characterized by higher levels of optimism. Clinical implications are discussed.