Autografting of burn wounds results in generation of donor site wounds. Here we measured donor site wound protein fractional synthesis rate (FSR) in a burn pediatric population and showed that FSR increases over time postsurgery and correlates with the length of hospital stay (LOS) normalized for total body surface area (TBSA) burn size. 3.9 ± 1.1 days after the grafting surgery patients participated in a metabolic study consisting of continuous infusion of l‐[ring‐2H5]‐phenylalanine and donor site wound punch biopsies. Donor site wound protein FSR was 10.4 ± 7.5%/day. Wound FSR demonstrated linear correlation with the time postsurgery (p<0.05). Multiple regression analysis showed that LOS/TBSA correlated with donor site wound protein FSR and time postsurgery (p<0.001) and the following equation describes the relationship: estimated LOS/TBSA=(FSR−12.95−1.414 × postsurgery day)/(−17.8). This equation predicted that FSR corrected for the postsurgery day when the metabolic study was conducted accounted for 67% of the variability (r2=0.673) in the LOS/TBSA. Donor site wound protein FSR correlated to LOS/TBSA of burn patients admitted to the intensive care unit. Measurement of protein deposition in regenerating donor site wound using stable isotope technique provides a quantitative measure of wound healing.