In healthy population, uric acid comprises the major component of 10-20% of renal stones. Extreme hiperuricaemia is seen in cancer patients with tumour lysis syndrome (TLS) which is classically associated with haematological malignancies with rapid tumour growth rates such as acute lymphoid leukaemia and high grade lymphomas. Primary melofibrosis (Agnogenic myeloid metaplasia-AMM) is a chronic myeloproliferative disease characterized by splenomegaly, a leukoerythroblastic blood picture, teardrop poikilocytosis and varying degrees of marrow fibrosis. Due to the increased extramedullary haematopoiesis, hiperuricemia may occur. However, TLS in patients with AMM is, according to the available literature, described just in one patient. In this paper we present a case of a 47-year-old male patient who was admitted to the hospital with symptoms of fatigue and small amount of urine, and clinical signs of plethora and enlarged spleen. The laboratory findings showed leuko-and erythrocytosis, increased levels of urea-BUN (32 mmol/l) and creatinine (766 mmol/l) as well as uric acid (920 mmol/l). The immediate abdominal ultrasound confirmed extreme splenomegaly, but also showed bilateral hydronephrosis of grade II-III with two stones in proximal part of right ureter and one in proximal part of left ureter as well as empty bladder. Stones were not seen on plain film. Since the patient was in complete anuria, with further rapid elevation of BUN and creatinine levels, bilateral ureteral stents were applicated together with extensive hydration, urine alkalization and administration of allopurinol which resulted in the complete recovery of kidney function. The bone marrow biopsy was also performed and histopathological diagnosis was: Hypercellulary phase of AMM.