Acute kidney injury, a rapid decline in glomerular filtration, is shown as increase in serum urea and creatinine concentrations and reduction of urine excretion. There are many known causes, but about some we can only assume. Creatine is produced in our bodies and also absorbed from food. So far several studies on the safety of creatine supplementations were published, but also unexpected side effects of creatine use were reported. We report a case of an 18-year-old athlete with acute renal failure, which could be caused by creatine supplementation intake. After cessation of creatine and the symptomatic treatment, including hemodialysis, the renal function went back to normal.