Media reports connecting UN peacekeeping duties by Canadian soldiers to their subsequent suicide prompted this study of peacekeeping as suicide risk. In a case-control design we retrospectively compared 66 suicides in the Canadian military between 1990 and 1995 with two control groups: (a) 2,601 controls randomly selected from the electronic military database and (b) 66 matched controls with complete personnel and medical data. We found no increased risk of suicide in peacekeepers except among a subgroup of air force personnel. Here confounding individual factors, isolation from supports, and possibly inadequate preparation for deployment elucidated their suicides. Theater of deployment (e.g., Bosnia) did not affect the suicide rate. Military suicides experienced psychosocial stresses and psychiatric illness more often than their matched controls. We conclude that although peacekeeping per se does not increase overall suicide risk, military life-styles may strain interpersonal relationships, encourage alcohol abuse, and contribute to psychiatric illness and suicide in a minority of vulnerable individuals irrespective of peacekeeping assignment. Careful selection, and preparatory military training that encourages intragroup bonding and mutual support, may protect against suicide risk.