The object of this study was to determine the factors associated with partner notification (PN) of sexually transmitted infection (STI) exposure among pregnant, low income, Mexican-American (MA) and African-American (AA) women and their male sexual partners. We used a cross-sectional analysis of 166 pregnant women with an STI, enrolled in a randomized controlled trial of behavioural intervention to prevent recurrent STIs. The primary outcome, PN, is notification of, or intent to notify male sexual partner(s) of STI exposure. Pregnant women with one (n = 136) versus multiple (n = 30) partners reported PN for 88.2% and 54.5% of male partners, respectively (P < 0.001). Multivariate logistic regression demonstrated three variables that independently predicted PN: a steady relationship, with one male sexual partner and recent (<30 days) intercourse with the partner. Among the low income, pregnant MA and AA women, the three relationship variables predicted 81.6% of PN and correctly classified 78.5% of males notified and 65.7% of males not notified.