While global scale-up of prevention of mother-to-child transmission of HIV (PMTCT) services has been expansive, only half of HIV-infected pregnant women receive antiretroviral regimens for PMTCT in subSaharan Africa. To evaluate social factors influencing uptake of PMTCT in rural Kenya, we conducted a community-based, cross-sectional survey of mothers residing in the KEMRI/CDC Health and Demographic Surveillance System (HDSS) area. Factors included referrals and acceptability, HIV-related stigma, observed discrimination, and knowledge of violence. Chi-squared tests and multivariate regression analyses were used to detect stigma domains associated with uptake of PMTCT services. Most HIV-positive women (89%) reported blame or judgment of people with HIV, and 46% reported they would feel shame if they were associated with someone with HIV. In multivariate analyses, shame was significantly associated with decreased likelihood of maternal HIV testing (Prevalence Ratio 0.91, 95% Confidence Interval 0.84-0.99), a complete course of maternal antiretrovirals (ARVs) (PR 0.73, 95% CI 0.55-0.97), and infant HIV testing (PR 0.86,. Community perceptions of why women may be unwilling to take ARVs included stigma, guilt, lack of knowledge, denial, stress, and despair or futility. Interventions that seek to decrease maternal depression and internalization of stigma may facilitate uptake of PMTCT.