We have reported a case of ureterocele and made some discussions on the etiology.The patient was 53 years-old male complaining of hematuria and residual feeling of urine. Cystoscopy and x-ray examination revealed a globular cyst about the size of apeagon egg. More than ten stones were recognized in the cyst, ureter and kidney of the same side. These stones changed their location by body movement probably because of the dilatation of the ureter. Moreover, the opposite ureter also contained one stone. The periodic alteration of the capacity of the cyst by the urinary elimination from theureter of the same side could not been recognized. The relation between the ureterocele and the stone formation was not distinct.