PIP: The incidence of HIV infections in the Caribbean, derived from official reports and selected studies, is assessed. AIDS has been reported in all countries except British Virgin Islands and Montserrat (excluding Bermuda and Puerto Rico). Cuba is the only country with a national survey: 147 cases out of 1 million were reported seropositive. Expressed by prevalence, AIDS is highest in the Bahamas (229/100,000), French Guiana (84.0), ranges between 17.5 and 16.0 in Barbados, Trinidad/Tobago, Guadeloupe, and Haiti, and least in the Dominican Republic (3.2). AIDS first appeared in Haiti in 1979. Examination of hospital records for Kaposi's sarcoma, and tests of frozen sera have failed to find evidence of HIV infection before that date. The magnitude of the epidemic is difficult to define because many countries have no national register. The 1st CDC case definition does not apply well to tropical areas. It is estimated that rates will rise 30% with application of the new CDC definition. Initially AIDS was spread primarily by homosexual contact among bisexual males, but since 1983, it has spread by heterosexual means in Haiti, the Dominican Republic and Trinidad, the 3 countries with the highest number of reported cases. In Haiti, heterosexual spread between couples occurred in 26% of females and 27% of males over 24 months. Reports of AIDS among women have doubled between 1979-1982. Perinatal spread is 30-40%, but transmission by breastfeeding has not been documented.