Heat illness in the British Armed Forces is a significant occupational risk. This paper analyzes reports of heat casualties occurring in Episkopi, Cyprus from January 1990 through December 1994. A total of 96 casualties were reported from 48 separate incidents. On seven occasions, three or more casualties occurred concurrently (maximum 19). There were 20 incidents causing 32 casualties from Cyprus-based units and 28 incidents causing 64 casualties from units visiting Cyprus. There was a clear seasonal variation of reports with the maximum number of reports occurring from May to August. The majority of reported casualties occurred when the Wet Bulb Globe Temperature was between 26 degrees C and 29 degrees C. Cyprus-based units had most casualties occurring as a consequence of forced marching whereas most casualties from visiting units occurred during military field exercise training. Visiting Territorial Army units had the highest incidence of heat casualties for visiting units. The majority of heat casualties were mild; there were only ten severe cases. It was not possible to identify any particular risk factors applicable to individuals except incomplete acclimatization. The study showed that the current guidelines used by the British Armed Forces do not prevent all heat casualties. It is not possible to estimate how many casualties are prevented by the guidelines. All incidents involving a serious casualty or multiple casualties should be investigated to determine whether the guidelines should be further amended.