Data from the First and Second Malaysian Family Life Surveys in 1976 and 1988, respectively, are analyzed to examine long-term trends in breastfeeding in Peninsular Malaysia, educational and ethnic differences therein, and the quality of retrospective data on infant feeding. The steady decrease between the mid-1950's and mid-1970's in breastfeeding was reversed to become a nearly monotonic increase since 1975. Part of the change is attributable to the changing composition of the Malaysian population. Over time, the percentages of births to subgroups with higher rates of breastfeeding--particularly Malays and more highly educated women--have increased. However, there is also evidence of changes in rates of breastfeeding within these subgroups. Many Malaysian infants have a total duration of breastfeeding (including with supplementation) considerably shorter than WHO's recommended four months of exclusive (unsupplemented) breastfeeding. Moreover, nearly all breastfed infants are first given supplementary food or beverage shortly after birth. Breastfeeding promotion efforts in Malaysia need to emphasize the appropriate timing of and types of supplementary feeding.