Expatriates comprise an important, but rarely studied subset of international travellers. This study was performed to assess the incidence of health events in an expatriate group and to evaluate factors affecting this incidence.A cohort of 2020 Foreign and Commonwealth Office (FCO) staff and partners living abroad were followed-up over 1 year. The main outcome measure was incidence of illness or injury serious enough to require consultation with a doctor. Data collection was by means of a self-administered questionnaire. Poisson regression was used to estimate the rates of health events and to test for association between health events and a number of independent variables.The incidence of health events was 21%. Trauma (incidence 5%), musculoskeletal disorders (incidence 4%) and infectious disease (incidence 3%) were the principal causes of morbidity. The incidence of psychological disorders was low (1%). Of significance, employees were at increased risk of morbidity when compared to partners, with a higher incidence of health events [incidence rate ratio (IRR) 1.4, 95% CI 1.1-1.9] and psychological disorders (IRR 5.9, 95% CI 1.0-34.1). Moreover, unaccompanied employees were at increased risk of health events (IRR 1.3, 95% CI 1.0-1.7), and of traumatic injury (IRR 2.3, 95% CI 1.3-4.3) when compared to accompanied employees.While the morbidity in FCO personnel is low in comparison to other expatriate groups, the higher risk of morbidity in employees and unaccompanied individuals merits further research, particularly to ascertain whether work demands, isolation or risk-taking behaviour are contributory factors.