Consumption of breast milk, liquids, and foods by 131 poor Peruvian infants was measured on 1661 child-days of observation during their first year of life. Breast-milk intake was estimated by 12-h test-weighing; macronutrients were analyzed in samples of milk. Other foods and liquids were weighed at preparation and consumption; nutrient contents were estimated from food composition tables. Mean energy intakes increased with age but declined from 95% to 78% of recommended amounts during the year. Mean protein intakes were generally above recommended amounts but more than one-third of infants received < 80% of the suggested safe intakes in the second (6-mo) semester. Breast milk was the major source of energy and protein during the first semester. Breast milk and cow milk together contributed more than half the energy and protein during the second 6 mo, when cereals were also an important source of energy and protein. Mean intakes of calcium, thiamin, and ascorbic acid were less than recommended at some ages but mean intakes of other selected micronutrients exceeded recommendations.