Background and Objectives: Reasons for intolerance to commercial amino acid-based formulas (cAAF) in in- fants diagnosed with cow’s milk protein allergy (CMA) remain unknown. We assume that minute amounts of proteins, presenting in the glucose polymers derived from corn starch (cGPs), can elicit the intolerance to the cAAFs observed in some infants with CMA. By replacing cGPs with glucose polymers derived from rice starch (rGPs), a new amino acid-based (nAAF) formula has been shown to be better tolerated than an existing cAAF. This study was carried out to corroborate the superiority of nAAF over a different commercially available cAAF. Methods and Study Design: Infants with CMA aged less than 4 months underwent a double-blind, placebo- controlled food challenge. They consumed each of the 2 test formulas for 14 days before switching to the other one. Following the 28-day challenge period, infants consumed the tolerated formula for 4 weeks as an at-home open challenge. Results: Out of 36 infants who completed the study, 18 were intolerant to the cAAF, seven of whom (38.8%) were also intolerant to the nAAF. Eleven of the 18 infants who were intolerant to the cAAF toler- ated the nAAF (p˂0.01). Conclusions: This study reconfirms that substitution of rGPS for cGPs in the amino ac- id-based formula improves tolerance of young infants with CMA.