Acute kidney injury (AKI) is associated with increased mortality and risk of chronic kidney disease (CKD). Whereas AKI is well known to occur frequently in patients with heat stroke, creatinine clearance levels of these patients have not been evaluated in literature. In this report, we present the case of a patient with increased creatinine clearance who developed AKI due to heat stroke. A 40-year-old male with no past medical history was admitted to the intensive care unit of our hospital due to AKI from heat stroke. Although he was diagnosed with stage 3 AKI at admission, his creatinine clearance, measured by a 12-h urine collection, was highly elevated to 230 mL/min/1.73 m 2 . His serum creatinine was decreased to the baseline level 12 h after admission, with fluid resuscitation. This case can suggest that creatinine clearance might be underestimated, although serum creatinine levels are elevated in AKI due to heat stroke.