There are considerable variations in the reported incidence of early and late epilepsy in children with lymphoproliferative diseases. The etiology of seizures in pediatric patients with hemoblastosis during polychemotherapy can be diverse: dysmetabolic, infectious, toxic, ischemic, posthemorrhagic. The treatment strategy selected by the neurologist largely depends on the causes of the paroxysmal conditions. When choosing the anti-seizure therapy one should consider the course of hemoblastoses and the possible effects of polychemotherapy. The article presents pediatric cases and the analysis of acute lymphoblastic leukemia with developing epileptic seizures.