Grafted skin has impaired blood flow and sweating responses necessary for heat dissipation. Heat acclimation improves temperature regulation in healthy individuals, but it is unknown whether heat acclimation improves temperature regulation of individuals with large areas of grafted skin. A 33-year-old woman with 75% total body surface area grafted skin 14 years postinjury performed upright cycling exercise at 45% peak oxygen uptake (50 W) for seven consecutive days in a climatic chamber set to 40 degrees C and 30% relative humidity. The daily goal was for this patient to exercise 90 minutes (with a 5-minute break at minute 45); however, exercise was stopped when an internal temperature (T.) limit of 39.5 degrees C was reached. The T-c limit was reached during minute 46 of exercise on day 1 of acclimation, but not until minute 65 of exercise oil day 7 of acclimation. The increases in T-c and heart rate during the first 45 minutes of exercise (the minimum duration completed for all acclimation bouts) were progressively mitigated with successive days of heat acclimation. Sweat sensitivity (the increase in sweat rate per 1 degrees C increase in T-c) in an area of uninjured skin increased by similar to 30% oil acclimation clay 7 relative to day 1. Heat acclimation improved thermal tolerance of this patient with a large area of grafted skin, which could increase safety and comfort during thermal stress and/or exercise.