Limited available evidence suggests that disaster support work may have negative effects. This study attempts to examine the impact of disaster-related stress on helpers offering psychological support to victims of two major disasters, and to identify potential moderating factors. Sixty-seven social workers were surveyed, measures being taken of psychological symptomatology and wellbeing, personality variables, social support, life events, and various aspects of disaster support work. Comparison with normative data suggested that subjects were experiencing significant levels of stress. Two major sources of disaster-related stress were identified: role-related difficulties and contact with clients' distress. Approximately one third of the variance in helper response could be explained by variables reflecting coping style, prior life events and the aforementioned aspects of disaster support work. Follow-up data at 12 months demonstrated persisting high levels of stress.