Background. A magnetic ball is a toy for children that can cause physical injury when used improperly. The injury of urethra and bladder caused by magnetic ball is rarely reported.

Case. Here we present a case of self-inflicted intravesical insertion of 83 magnetic balls by a 10-year-old boy. Preliminary diagnosis was made by a plain radiograph of the pelvis and ultrasonic examination of bladder and all the magnetic balls were removed under cystoscopy successfully.

Conclusions. For children with recurrent bladder irritation, the possibility of bladder foreign body should be considered. Surgery is an effective method. For patients without serious complications, cystoscopy is the gold standard for diagnosis and treatment.

Keywords: children, intravesical, magnetic balls, self-inflicted