In 1991 a computerized, comprehensive epidemiological surveillance system was developed to monitor health trends in approximately 25,000 acutely displaced Kurds in Nowsood and Saryas refugee camps, Bakhtaran region, Northwestern Iran. In addition, community‐based surveys offered information unobtainable from health facilities. Weekly population movements, attack rates, point‐prevalence estimates, and case fatality ratios were calculated, and the data were analysed and compared. The overall crude mortality rate (CMR) in the camps under study was still 9 times higher than the reported CMR for Iraq. Health problems with very low rates (less than 1.0/ 1,000 population/week) included the triad of measles, meningitis and tetanus. However, morbidity for the most common conditions (acute respiratory infections, diarrhoea, skin infections, eye diseases and, finally, typhoid fever) was shown to increase at the end of the intervention, highlighting that the pressure of repatriation on refugees made them progressively worse. This article concludes that epidemiological surveillance systems should be implemented during mass‐migrations in developing countries also in post‐emergency settings. Furthermore, surveillance appears to be indispensable in order for the international agencies to keep abreast of events and to safeguard human rights when international attention s