The weaning process varies widely among different cultures as to when the practice is initiated and terminated; in the variety, quality, and quantity of the weaning foods; and in the manner in which the endogenous food is provided. The variations in practices range from providing a food source even before the first breastfeeding to feeding nothing but breast milk for as long as 9 to 12 months, and include feeding from a cupped hand to use of a modern feeding bottle. The advice often given healthy mothers is to breast-feed for as long as possible and compatible with life-style. Most often, when breast-feeding is prolonged, the practice is to provide some complementary food from the early postpartum months onward. However, among some poor traditional societies and in deprived environments, this food may be limited and monotonous in flavor and texture. The monotony of the diet may act synergistically with the consequences of repeated infectious morbidity, and result in chronically depressed appetite and limited acceptance of additional food in quantity and variety at the time when this becomes critical for meeting the nutritional needs of the growing infant. The serious malnutrition prevalent in the 1 to 3 year olds in many deprived environments may have its antecedent etiology in the complementary feeding practices established in the first year of life. Effective interventions to reverse growth faltering of infants reared in deprived environments where breast-feeding is prolonged may require increased attention to providing variety in the weaning diet from at least 4 months onward.