This paper uses unique data from the 1976-77 and 1988-89 Malaysian Family Life Surveys (MFLSs) to address two questions: 1) Are the reported reasons for not initiating breastfeeding or for stopping breastfeeding reliable based on indices of agreement of responses between the two surveys and/or conventional multivariate analyses of overall versus reason-specific breastfeeding duration? 2) What do we gain by separating analyses of age-specific breastfeeding cessation by reported reasons? The analyses are based on responses of mothers to questions about the duration of breastfeeding and why they never initiated or stopped breastfeeding. The authors investigate the reliability of data on reasons for no or short breastfeeding by comparing reports 12 years apart (1976 and 1988) about the reason why a particular child did not breastfeed or stopped breastfeeding. The authors find that the reported reasons for no/short breastfeeding are quite reliable in general, and that the data on reason-specific breastfeeding practices are indeed informative in verifying hypotheses about the influences on breastfeeding patterns. In both surveys, no/insufficient milk is the most frequently given reason for no or short breastfeeding. The covariates considered here that significantly affect whether the child is breastfed and the duration of breastfeeding (sanitation and water facilities, mother's education, employment, ethnicity, place of residence, child's birthweight and birth cohort), also affect the reported reason why the child was not breastfed or stopped breastfeeding.