There are previous reports of osteonecrosis among Nigerians with sickle cell diseases and some other medical conditions. To the best of the authors' knowledge there is, however, no known such report attributed to chronic myeloid leukaemia, especially in Nigeria. Apart from presenting this as the first report, it is also to emphasize the need for early full blood count in persons presenting with otherwise non-haematological condition. The case note of the patient and the available literature on the subject were used. The 15-year-old girl who presented with a fifteen-month history of right hip joint pain and progressive abdominal swelling with weight loss for five months was found to have chronic myeloid leukaemia and avascular necrosis of the right femoral head. Her gait and walk improved remarkably within two weeks of commencing cytoreductive therapy. However, she still uses crutches due to the extensive bone damage from the prolonged impaired blood supply caused by chronic myeloid leukaemia before presentation. Osteonecrosis of the femoral head can complicate chronic myeloid leukaemia from hyperviscosity-induced leucostasis. Early simple peripheral blood examination in diseases presenting with otherwise non-haematological symptoms will reduce, if not prevent, severe complications of diseases.