Since 2011, endoscopic correction of vesicoureteral reflux using dextranomer-hyaluronic acid copolymer (Deflux®) has been widely accepted in Japan due to its safety and minimally invasive nature. However, long-term complications are unknown. We present a case of Deflux® implants calcification mimicking distal ureteral calculi in a 12-year-old boy with a history of Deflux® injection performed at three years of age for primary VUR. We should be aware of this complication to avoid misdiagnosis and unnecessary invasive examination such as radiological imaging or endoscopy.