The study's objective was to examine the relationship between cesarean section delivery and the initiation of breastfeeding in a representative sample of 1695 Puerto Rican women aged 15 to 49 years, who delivered their last healthy singleton child in Puerto Rico between 1990 and 1996. Secondary analysis of data collected in the population-based cross-sectional study Puerto Rico Reproductive Health Survey was performed. Bivariate and multivariate logistic regression analyses were used to examine the crude and covariate adjusted association between type of childbirth and initiation of breastfeeding. Overall, 36% of all births were performed by cesarean section, while initiation of breastfeeding was achieved by 61.5% of the women. Cesarean section was negatively related to breastfeeding initiation in multivariable logistic regression models (odds ratio=.64; 95% CI=0.51-0.81) after controlling for confounding variables. Intervention programs that aim to promote breastfeeding and that provide special assistance to women undergoing this procedure should be developed.