Adequate nutrition and growth is vital in pediatrics. Breast milk alone might not be able to satisfy the nutrition needs of an infant with renal disease. Similac PM 60/40 (Abbott Laboratories, Abbott Park, IL, U.S.A.) is a low-iron infant formula indicated for infants who would benefit from a lowered mineral intake. It is the only infant formula marketed in the United States for infants with renal impairment. The objective of the present case study was to examine whether Renastart, a pediatric renal formula (Nestlé Health Science, Florham Park, NJ, U.S.A.), could be used alongside expressed breast milk (EBM) to meet the nutritional needs of an infant with renal disease, while maintaining normal serum electrolytes.A 9-month-old infant received EBM with Similac PM 60/40 treated with Kayexalate (Concordia Pharmaceuticals, Bridgetown, Barbados) because of hyperkalemia. That formulation was not well tolerated, and the infant's growth trajectory declined. The infant was then switched to EBM with Renastart. During this intervention, growth trends; formula volume; kilocalories and protein grams consumed per kilogram weight; episodes of emesis; serum Na, K+, Ca, and phosphorus; blood urea nitrogen; and creatinine were collected.Results showed an increase of formula intake, an improvement in weight and linear growth, and normal serum levels of Na, K+, and Ca, but low serum phosphorus.A combination of Renastart and EBM can be safely and effectively used to meet the needs of an infant with renal disease. Close monitoring of protein intake and electrolytes is necessary, and supplementation with phosphorus should be considered. Larger studies are needed to further confirm the benefits of Renastart in infants.