BACKGROUND: Heat-related illness, including heat exhaustion and heat stroke, is seen as a major risk for athletes with a physical impairment. OBJECTIVE: Primary: To survey the illness statistics during the 2015 Para Athletics World Championships and report on any cases of significant heat-related illnesses. Secondary: To document the heat countermeasures taken on behalf of the organizing committee. DESIGN: Retrospective audit. SETTING: Medical records collected at medical centers during the 2015 Para Athletics World Championships. PARTICIPANTS: Athletes participating in the 2015 Para Athletics World Championships. METHODS: Illness statistics and records of hospitalizations of athletes participating in the championships were recorded by the medical officials during the precompetition (3 days) and competition (10 days) periods. Furthermore, wet-bulb globe temperatures (WBGTs) were measured at the competition venues. MAIN OUTCOME MEASUREMENTS: Incidence rates of illness during the precompetition and competition periods. RESULTS: WBGTs ranged from 24.6 degrees C to 36.0 degrees C, regularly exceeding the American College of Sports Medicine (ACSM) and International Association of Athletics Federations (IAAF) guidelines for cancelation in the morning both during the competition (ACSM, 52%; IAAF, 97%) and precompetition periods (ACSM, 75%; IAAF, 100%). These guidelines were not exceeded as regularly during the evening and noon for both the precompetition and competition periods (ACSM, 0%-5%; IAAF, 0%-58%). The illness incidence rate was 2.89 per 1000 athlete-days (incidence proportion = 3.76%; confidence interval = 2.69%-4.83%). Only seven cases of heat-related illness were recorded, of which three required hospitalization. CONCLUSION: This study indicates low rates of illness, including hospitalization and intravenous administration for heat-related illness among athletes participating in the 2015 Para Athletics World Championships. LEVEL OF EVIDENCE: III.