This study attempts to assess infant breastfeeding practices among 200 low income families in New York City and in New Jersy, and to measure differences in feeding practices among 5 different ethno-cultural groups, U.S. Blacks, West Indians, Puerto Ricans, Haitians, and Hispanics. 58.5% of mothers were not born in the U.S., but the majority, or 77.5% had lived in the U.S. for more than 5 years. Only 6% of families reported an annual income above $10,000. 29% of mothers in the entire study group attempted breastfeeding, the majority being West Indian mothers (64%), followed by Puerto Ricans (34%), Hispanics (33%), Haitians (21%), and U.S. Blacks (15%). Average duration of breastfeeding was highest among Hispanics, with 10.2 weeks, and lowest among Haitians, with 2.3 weeks. 94.5% of mothers had used an artificial formula feeding in conjunction or as a substitute for breastfeeding during the first 4 months of infancy, the most widely used milk feeding being Similac, 41.5%, followed by ordinary cow's milk, 31%; less than 10% of families were using formula feeding beyond 6 months of age. 1/3 of mothers reported using iron supplements in addition to the iron already contained in some formulas. 17 infants had diets deficient in iron intake; those infants were fed an iron-poor formula, and half of them presented evidence of iron deficiency anemia. Introduction of solid foods differed little among the various ethnic subgroups. This study corroborates other published reports in indicating that there is a growing interest in breastfeeding among the lower socioeconomic population. Still, education on proper nutrition for infants is lacking within the same group, and infant feeding counseling programs should be sensible to such lack of professional guidance.