The latency of infection in leprosy is long so that new cases may present several years after emigration from endemic areas. This is of concern to the health authorities in Kuwait, since there is a sizeable immigrant population. An epidemiological study of new cases was, therefore, conducted to assess the extent of the leprosy problem. A total of 121 (99 male, 22 female) consecutive new leprosy patients were diagnosed nationwide over a six-year period (1983-1988). Over 95% of the patients were foreign born, emphasizing that the problem in Kuwait is mainly a reflection of immigration patterns. There were 74 cases of Asio-Indian origin, 13 Oriental and 34 Arab (including two Kuwaiti). This represents a respective mean incidence of the disease in Kuwaitis and other nationalities of 0.49 and 18.92 per 100 000 per year. Polar lepromatous (LL) leprosy was the most frequent type in the Arab group (44.1%) and polar tuberculoid (TT) the most frequent in the Asio-Indian group (37.8%). LL and borderline lepromatous (BL) types of leprosy were significantly more frequent in patients over 45-years-old and in females (P<0.05), contributing to the higher rate of LL in the Arab cases. The mean lag time from symptoms onset to presentation to doctor was 9,4 (range 0-192) months, with lepromatous cases tending to present later than other types. The longest lag times occurred in Arab women with LL, suggesting that cultural influences may delay presentation of leprosy. The mean interval from presentation to diagnosis was 4.1 weeks. The mean latency from entry into Kuwait to diagnosis was 44.7 (range 0-180) months; which stresses the need for physicians to remain vigilant in considering leprosy, especially in any patient with dermatological, neurological or ophthalmic manifestations of disease.