A longitudinal feeding study of 154 infants in Southwest Virginia was conducted during 1978-1980. The incidence of vitamin and mineral supplementation among these infants was the focus of the retrospective study discussed here. With the use of the Nutritional Analysis System of Louisiana State University, nutrient adequacy levels were determined. Vitamin D, vitamin E, folacin, vitamin B-6, and iron were the problem nutrients identified through this analysis. Inappropriate infant feeding practices such as the use of low iron formulas, the use of cow's milk, and the consumption of inadequate milk volume were blamed for these dietary deficiencies. Routine vitamin supplementation was common among infants of all feeding types. While much of the supplementation was unnecessary, large percentages of infants demonstrated a need for it. The exception was vitamin A. None of the infants who received supplemental vitamin A had inadequate dietary intakes of this nutrient. Supplementation was not shown to have an effect on weight or length gain measurements. Parents should be given specific infant feeding instructions prior to hospital discharge. Included should be a list of the circumstances which would indicate the need for supplementation. / M.S.