Summary Leptospirosis is endemic in most of the Caribbean region, though poorly reported. Semi-arid islands, such as Curaçao, have very few, if any, cases, while Dominica (annual rainfall >200“) had at least 23 severe cases/100 000/year in 1989 and 1990, a figure nearly 200 times higher than for England and Wales in 1985–1989. Most information on leptospirosis in the non-Spanish speaking Caribbean comes from Trinidad, Barbados and Jamaica. The leptospiral epidemiology of Barbados is apparently the simplest of these three; here three serovars of Leptospira interrogans (bim, copenhageni and arboreae) cause 97% of cases of severe human disease. The most complex is probably that of Trinidad, where 17 serovars have been isolated from man and 11 animal species; 6 of these serovars were first found on the island. Commensal rodents are thought to cause most of the leptospirosis in the region. Dogs are also important sources of infection, though not necessarily of serogroup Canicola. Seropositivity to a variety of serovars can be found in high proportions (>50%) of livestock, but pathogenic effects are not thought to be common. Although Sejroe is occasionally detected serologically, L. hardjo and other well-known livestock pathogens, such as L. pomona and L. tarassovi, do not seem to be economically important at present.