The aim of the paper is to test the basic assumptions underlying the theory of reasoned action (TRA) for exclusive breastfeeding behavior taking place in the rather complicated social environment of women who have just given birth. The paper aims (i) to argue that normative rather than attitudinal considerations are more important in engaging the correct breastfeeding behavior, and (ii) to demonstrate that the TRA concept of social norm should be treated as a multi-layered construct which involves several enabling factors in predicting complex behaviors such as breastfeeding. Data were collected in three phases as part of a prospective cohort follow-up design. The first phase of data collection was conducted in the hospital with mothers after the delivery. Two follow-up questionnaires were administered at the end of the first and second months. Results did not confirm the assertions of the TRA. Logistic regression models and multiple regression analyses indicated that intention and belief/attitude measures taken at the time of birth did not predict end-of-first-month full breastfeeding behavior. Overall, results revealed that intention by itself was not a strong determinant of breastfeeding unless it was conditioned by enabling factors such as social support and subjective norms regarding breastfeeding.