BackgroundTeratomas are tumors consisting of two or three germ layers, seen commonly during childhood. Teratomas have been reported to occur in various sites and organs. Bladder teratoma is a very rare extragonadal tumor, moreover in adults. Although teratomas are known as benign lesions in childhood, they may act as malignant tumors when detected during adulthood. This requires total tumor resection, particularly in adult cases, and the addition of radiotherapy and chemotherapy in cases with the potential of malignancy.Case presentationA very rare case of teratoma of the bladder in a 17-year old Asian girl is presented. The patient had chief complaints of hematuria. The diagnosis was made on cystoscopy and confirmed histopathologically. Complete excision was possible. To the authors’ knowledge, this is the first such case reported from Indonesia and the South East Asian region.ConclusionA bladder teratoma mimics the presentation of a bladder stone, clinically and radiologically. A dermoid cyst should be considered as a differential diagnosis, especially when the stone appears to be confined to the bladder wall during examination.