Police officers represent a special population who cope with multiple and conflicting demands on a daily basis and therefore present a high risk for posttraumatic stress. The study investigates impact of hardiness and coping strategies of perceived stress at personnel involved in future international peacekeeping missions. The sample consists of 116 officers who filled in three questionnaires about hardiness (Bartone, 1989), coping strategies (Billings & Moss, 1981) and professional and life stressful events. We conducted regression analyses with the three components of hardiness (commitment, control, challenge) and the three coping strategies (active coping, active behavioural, avoidance) as independent measures and the perceived level of both professional and life stress as dependent variables. The results showed that hardiness explained better than coping strategies both professional stress (R-Sq = 13% vs. 9%) and life stress (R-Sq = 16% vs. 9%). Psychological hardiness seems to be an important feature for understanding stress tolerance in highly demanding occupations. The results are interesting especially because all the subjects represent a very robust population used to deal with many stress factors.