A 24-yr-old woman presented with gross haematuria and a huge tumour of the right bladder wall. At transurethral resection, a solid tumour was seen covered with normal mucosa. The pathological evaluation revealed a solitary fibrous tumour (SFT) of the urinary bladder. For final treatment, a partial cystectomy was performed; tumour-free margins were ensured by frozen-section analysis. This is the first case in the literature presenting intravesically in a young woman. Due to the difficulty in discriminating between malignant and benign growth pattern of this tumour entity, a regular follow-up after conservative treatment is mandatory.