Osteoarthralgia is a common symptom at the beginning of acute lymphoblastic leukaemia (ALL). It occurs in 40% of cases. Still arthritis that precedes haematological malignancies is very rare. However in every case of arthritis of unknown origin or drug resistance arthritis the bone marrow biopsy is required. We present 3 cases of osteoarthralgia that precedes ALL by 2.5-7 months.