Vaccination of infants against human immunodeficiency virus type 1 (HIV-1) may prevent mother-to-child HIV-1 transmission. Successful trials and immunization efforts will depend on the willingness of individuals to participate in pediatric vaccine research and acceptance of infant HIV-1 vaccines. In a cross-sectional study, pregnant women presenting to a Nairobi antenatal clinic for routine care were interviewed regarding their attitudes toward participation in research studies and HIV-1 vaccine acceptability for their infants. Among 805 women, 782 (97%) reported they would vaccinate their infant against HIV-1 and 729 (91%) reported willingness to enroll their infant in a research study. However, only 644 (80%) would enroll their infants if HIV- 1 testing was required every 3 months and 513 (64%) would agree to HIV-1 vaccine trial participation. Reasons for not wanting to enroll in a pediatric HIV-1 vaccine trial included concerns about side effects (75%), partner objection (34%), and fear of discrimination (10%), HIV-1 acquisition (8%), or false-positive HIV-1 results (5%). The strongest correlate of pediatric vaccine trial participation was maternal willingness to be a vaccine trial participant herself; in univariate and multivariate models this was associated with a 17-fold increased likelihood of participation (HR 17.1; 95% CI 11.7-25; p < 0.001). We conclude from these results that immunizing infants against HIV-1 and participation in pediatric vaccine trials are generally acceptable to women at high risk for HIV-1 infection. It will be important to address barriers identified in this study and to include male partners when mobilizing communities for pediatric HIV-1 vaccine trials and immunization programs.