A seroepidemiologic study on a cross-sectional sample of blood donors was carried out in Guadeloupe, a French West Indies island, to estimate the prevalence of hepatitis B virus (HBV) markers, and to investigate the influence of age, socioeconomic, and geographic factors on prior HBV infection. Blood specimens and sociodemographic data were collected in 1989 from 2,339 blood donors residing on the island. A total of 73 (3.1%) of 2,339 were found to be HBV surface antigen carriers, and 518 (22.1%) were positive for antibody to HBV core antigen. Among them, 61 were positive for both markers and consequently 530 persons (22.7%) were considered to have evidence of prior HBV infection. Multivariate logistic regression analyses identified age and low socioprofessional status as being related to HBV infection, as in many endemic areas. In addition, some major geographic risk factors were highlighted, reflecting a strongly hyperendemic situation in specific areas and the potential influence of horizontal transmission or unknown environmental factors on these particular populations.