To compare the seroprevalence of HIV in Jamaican pregnant women with that in substance abusers, two groups of antenatal patients were studied, one (A) attending a public hospital clinic and the other (B) attending private clinics. The HIV seroprevalence in the antenatal patients was compared with that in the substance abusers, group C, in 1996 and five years later in 2001. HIV antibody was determined by enzyme immunoassay. The HIV seroprevalence in group A more than doubled (1.6%-3.8%) in five-years, 1996-2001. There were no seropositives in group B. In group C, the seroprevalence rose from 2.08% in 1996 to 5.76% in 2001. There was indication that group A might no longer be considered "low risk", as there was no significant difference from group C in HIV seroprevalence in 1996 and 2001. The trend seen in this study is worthy of further investigation.