Primary signet-ring cell adenocarcinoma of bladder is a rare neoplasm, usually seen in middle age adults. We report the case of an 18-year-old man who presented with intermittent gross hematuria. Computed tomography imaging showed multifilling defects in the bladder. The patient underwent a transurethral resection of the bladder tumor. Histological findings were consistent with poorly differentiated mixed mucinous and signet-ring cell adenocarcinoma. We ruled out other possible origins of tumor by gastrointestinal endoscopy and colonoscopy. The patient was treated with radical cystectomy with prostate and seminal vesicle sparing technique and orthotopic diversion using "W" ileum pouch with pelvic lymphadenectomy to the bifurcation of the aorta was done. Six-month follow-up of patient showed normal conditions without metastatic spread or any recurrence.