ABSTRACT: BACKGROUND: Primary lymphoma of the bladder is a rare condition with less than 100 cases reported in the literature. CASE PRESENTATION: Here we present the case of a 64 year old woman with a 9 month history of haematuria, frequency, urinary incontinence and weight loss. Cystoscopy revealed a solid tumour throughout the whole bladder wall and a vesico-vaginal fistula. This was confirmed on CT scan which also showed no other organ involvement and bilateral hydronephrosis. Trans urethral biopsies taken at cystoscopy revealed Non-Hodgkin's Lymphoma. The patient had a nephrostomy inserted and is currently receiving a course of chemotherapy. CONCLUSION: We believe this is the first documented case of primary bladder lymphoma causing a fistula and therefore we suggest that lymphoma should be included in the differential for any patient with a fistula involving the bladder.