Leukemia-associated myelitis is a rare but underestimated complication. It has a different etiology associated with both, the main disease and its treatment methods. It requires differential diagnosis with funicular myelosis, polyradiculoneuropathy, tumor and hemorrhagic formation, stroke, dysmetabolic manifestations, as well as with the consequences of treatment of the underlying disease using radiation, cytostatic, targeted therapy.It should also be differentiated from paraneoplastic myelopathy and progression of the underlying disease. However,with the help of neuroimaging methods, it can be detected more recently than a detailed clinical picture appears. A case report of myelopathy in a 31 year old patient with acute lymphoblastic leukemia is presented. Treatment of the underlying disease was carried out with the use of chemotherapy, radiation therapy, allogeneic hematopoietic stem cell transplantation and targeted therapy. The nature of the disease,i.e. recurrent course of acute lymphoblastic leukemia, the variety of treatment methods, and the absence of focal changes in neuroimaging in the zone that determines clinical manifestations, made it necessary to consider a wide range of possible etiological factors for the development of myelopathy. Myelopathy was confirmed by MRI 2.5 months after the debut of neurological symptoms, which corresponds to modern concepts and time criteria for visualization in neurooncology. The article presents the criteria for diagnosing myelopathy, a complication of acute lymphoblastic leukemia. It should also be differentiated from However, with the help of neuroimaging methods, it can be detected more recently than a detailed clinical picture appears.