A rare case of phyllodes tumour arising in the seminal vesicle is reported here. A 59-year-old male presented with lower abdominal discomfort and symptoms of bladder outlet obstruction for 1 year. Transrectal ultrasonography and pelvic computed tomography and magnetic resonance imaging demonstrated a large mass posterior to the bladder and anterior to the rectum. Tumour excision and right seminal vesiculectomy were performed via a transvesical approach. The left seminal vesicle, bladder and prostate were not involved. The patient had an uneventful post-operative course and recovered well. There was no evidence of recurrence or metastasis during 22 months of regular follow up. The diagnosis, histological classification, treatment and prognosis of this case are presented together with a review of the literature. It is suggested that the behaviour of phyllodes tumour of the seminal vesicle is related to its histological parameters.