A ureteric inflammatory polyp is an extremely rare cause of hydronephrosis in children. This study reports the case of a 6-year-old boy with a recent COVID-19 infection who suffered from acute hydronephrosis due to multiple ureteral inflammatory polyps. Excision and ablation of these polyps were performed via ureteroscopy, but ureteral strictures were noted after excision. This study also reviews the literature regarding previous clinical cases.