To compare rates of serologic concordance in the female sex partners of men with HIV-1 and HIV-2 infections, and to determine the serologic status of sex partners of men who reacted serologically to both viruses. Cross-sectional study. Infectious diseases service in a University Hospital in Abidjan, Côte d'Ivoire (West Africa). Hospitalized men reactive on synthetic peptide-based tests to HIV-1, HIV-2 or both viruses (dually reactive), and their spouses visiting them in hospital. Serologic status of female spouses of seropositive men. The serologic status of 540 spouses of 490 HIV-1- and/or HIV-2-positive, hospitalized men was studied. Similar proportions of spouses of HIV-1-infected men (49%) and HIV-2-infected men (44%) were concordantly seropositive. The overall prevalence of infection in spouses of dually reactive men (72%) was significantly higher than in spouses of other men; 44% of these spouses were infected with HIV-1, 8% with HIV-2, and 20% were themselves dually reactive. Considering only the seropositive female spouses of men monotypically reactive to HIV-1 or HIV-2, and the male spouses of women monotypically infected, rates of serologic discordance were significantly greater in men (24%) than women (7%). Men were likely to have been infected earlier than women because of their HIV-associated illness; also, men more frequently had serologic profiles indicative of infection outside of the union. Rates of serologic concordance in spouses of men with advanced HIV-1 or HIV-2 infection were similar (44-49%). Dually reactive hospitalized men frequently (72%) had seropositive sex partners, most of whom were HIV-1-positive. Dual reactivity was also frequent in these spouses, suggesting transmission of both HIV-1 and HIV-2, or of a cross-reactive strain, and a minority of partners were infected with HIV-2 alone. Prospective studies of discordant couples using quantitative molecular diagnostic techniques are required for better understanding of dual reactivity and transmission of HIV-1 and HIV-2.