Ureteral obstruction caused by a fungal ball is rare. Diabetes mellitus and immunocompromised conditions constitute the predisposing factors. Urosepsis due to unilateral ureteral obstruction with a fungal ball is extremely rare. The radiologic findings of fungal ball have been described as nonspecific. We report on a female patient with urosepsis that occurred by unilateral ureteral obstruction by a fungal ball, mimicking a ureteral stone. She was managed with systemic antibiotics, percutaneous nephrostomy, and ureteroscopic fungal ball removal.