Both muscle and brown adipose depots are implicated in sustaining the hypermetabolic state after burn injury. Previous research has described the morphological and metabolic changes of peripheral white adipose tissue (WAT) after burn injury in the pediatric burn population. Pediatric post-burn WAT demonstrates brown-like changes, including up-regulation of uncoupling protein 1 (UCP-1), a marker of increased thermogenesis, and decreased vacuole size, an indicator of increased metabolic load. Clinical management of burn hypermetabolism in adults has been extrapolated from studies in children; however, significant differences exist between pediatric and adult adipose metabolism. Our study aimed to characterize peripheral adipose browning in adult patients following burn injury. Under an institutional IRB approved protocol, discarded adipose tissue was collected, de-identified, and evaluated over a two-year period. Patients under age 18 were excluded. H&E stained tissue sections were scanned with whole slide imaging and analyzed with a vacuole algorithm. Adjacent tissue sections were immunohistologically evaluated for UCP-1 and scored for intensity and percent cell staining. Statistical analysis included univariate and multivariate analyses controlling for patient demographic and burn characteristic data. Of the burn samples collected, 72 burn samples (57 patients) and 15 control samples (15 non-burn patients) were examined. Demographic data was similar in both groups except gender (64% men burn, 27% men non-burn, p= 0.011) and collection site (23% torso burn, 87% torso non-burn, p<0.001). Average vacuole area was similar between burn and non-burn samples; however, average vacuole diameter was significantly different (3.4 vs. 3.1, p=0.038). Burn samples showed greater intensity and percentage of UCP-1 expression than non-burn samples (p <0.001). Adjusting for other patient characteristics, samples collected 8–14 days post-burn had an increase in UCP-1 intensity compared to samples collected 1–7 post-burn. Moreover, increased UCP-1 expression was associated with a larger vacuole diameter (p<0.001) and area (p<0.001). Consistent with previous studies, our findings indicate browning of adult WAT post burn, as indicated by increased UCP-1 expression. Unlike pediatric burn WAT, adult burn WAT has fewer and larger lipid droplets per cell, suggesting brown-like cells in adult burn WAT have differing morphology than what has been shown in pediatric studies. Understanding adult burn fat morphology and UCP-1 expression may impact current standard treatment of hypermetabolism after burn injury.