The aim of the study was to analyze the characteristics of posterior reversible encephalopathy syndrome (PRES) cases treated at 10 different institutions in our country. Fifty-eight patients diagnosed with PRES were included in this study. The data of PRES cases from 10 departments of pediatric hematology/oncology were analyzed. The mean age of the patients at the time of diagnosis of PRES was 8.95 +/- 3.66 years. Most patients (80.4%) had a primary diagnosis of acute leukemia. Patients received chemotherapy (71.4%) and/or used steroids within 14 days before the diagnosis of PRES (85.7%). Hypertension was found in 83.9% of the patients. Twenty-six patients had infections and 22 of them had febrile neutropenia. The most common electrolyte disorders were hypocalcemia, hypomagnesemia, and hypopotassemia. Six patients had tumor lysis syndrome and 4 had inappropriate antidiuretic hormone syndrome. Magnetic resonance imaging was used for diagnosis in all patients. The most commonly involved regions by magnetic resonance imaging were occipital (58%), parietal (51%), and frontal lobes (45%), respectively. Twenty-five patients required intensive care and 7 patients were intubated. In conclusion, PRES may develop during the follow-up and treatment of hematological diseases. In addition to steroid and intense combined chemotherapies, immunosuppressive agents and hypertension are also factors that may be responsible for PRES.