Voluntary counseling and testing (VCT) for couples (CVCT) is an important HIV-prevention effort in sub-Saharan Africa where a substantial proportion of HIV transmission occurs within stable partnerships. This study aimed to determine the acceptance and effectiveness of CVCT as compared to individual VCT (IVCT). 1,521 women attending three antenatal clinics in Dar es Salaam were randomized to receive IVCT during that visit or CVCT with their husbands at a subsequent visit. The proportion of women receiving test results in the CVCT arm was significantly lower than in the IVCT arm (39 vs. 71%). HIV prevalence overall was 10%. In a subgroup analysis of HIV-positive women, those who received CVCT were more likely to use preventive measures against transmission (90 vs. 60%) and to receive nevirapine for themselves (55 vs. 24%) and their infants (55 vs. 22%) as compared to women randomized to IVCT. Uptake of CVCT is low in the antenatal clinic setting. Community mobilization and couple-friendly clinics are needed to promote CVCT.