Introduction: Focal segmental glomerulosclerosis (FSGS) is a serious condition causing glomeruli damage and leading to nephrotic syndrome and renal failure. One of its causes is the prolonged use of anabolic-androgenic steroids (AAS), which has become a common trend among young athletes who are in a majority not aware of its side effects. Aim: This study aimed to present an influence of performance-enhancing drugs (including AAS) combined with high-intensity training on renal failure, referring to a clinical case report. Case study: The study presents a 25-year-old male who was admitted to Nephrology Clinic with hematuria, proteinuria, elevated creatinine values, and hypertension. During hospitalization, a kidney biopsy was performed, which confirmed FSGS. Results and discussion: In our patient’s case, FSGS was caused by overusing performance-enhancing drugs (including AAS) for 10 years, a high-protein diet, and high-intensity training. When the patient had discontinued the use of all the performance-enhancing drugs and had begun appropriate treatment, the renal function parameters improved. Conclusions: We conclude that overusing multiple performance-enhancing drugs may lead to renal failure and FSGS even in young adults with no congenital or immunological contributing factors. Thus such therapy should be disadvised especially to young athletes wanting to quickly improve their muscle mass.