Although 2 earlier studies reported that aromatic amino acid (AAA) supplementation of children with severe acute malnutrition (SAM) improved whole-body protein anabolism during the early postadmission (maintenance) phase of rehabilitation, it is not known whether this positive effect was maintained during the catch-up growth and recovery phases of treatment. This study aimed to determine whether supplementation with an AAA cocktail (330 mg · kg−1 · d−1) vs. isonitrogenous Ala would improve measures of protein kinetics in 22 children, aged 4-31 mo, during the catch-up growth and recovery phases of treatment for SAM. Protein kinetics were assessed by measuring leucine, phenylalanine, and urea kinetics with the use of standard stable isotope tracer methods in the fed state. Supplementation started at the end of the maintenance period when the children were clinically/metabolically stable and continued up to full nutritional recovery. Three experiments were performed: at the end of maintenance (at ˜ 13 d postadmission), at mid-catch-up growth (at ˜23 d postadmission when the children had replenished 50% of their weight deficit), and at recovery (at ˜48 d postadmission when they had achieved at least 90% weight for length). Children in the AAA group had significantly faster protein synthesis compared with those in the Ala group at mid-catch-up growth (101 ± 10 vs. 72 ± 7μmol phenylalanine · kg−1 · h−1P<0.05) and better protein balance at mid-catch-up growth (49 ± 5 vs. 30 ± 2 μmol phenylalanine · kg−1 · h−1; P < 0.05) and at recovery (37 ± 8 vs. 11 ± 3 μmol phenylalanine · kg−1 · h−1; P < 0.05). We conclude that dietary supplementation with AAA accelerates net protein synthesis in children during nutritional rehabilitation for SAM. J. Nutr. 144: 660-666, 2014.