BackgroundThe seroprevalence of hepatitis B among children with cancer in Sudan is unknown. The aim of this study was to detect the seroprevalence of hepatitis B virus (HBV) infection in children with malignancy and its correlation with different risk factors.ProcedureThis study included 178 children with malignancy presenting to the Radioisotope Center in Khartoum during the period of May–July 2011. Sixty‐four healthy children served as controls. Sera from patients and controls were investigated for HBV total anti‐core antibody, HBV surface antigen (HBsAg), and HBV e antigen (HBeAg).ResultsHBV total anti‐core antibody was positive in 71/178 (39.9%), HBsAg was positive in 38 (21.3%), and HBeAg was positive in 19 (10.7%). Blood product transfusion, surgical exposure, chemotherapy, malignancy type, and sex did not affect the seroprevalence of HBV in this study. Vaccinated children had reduced rates of exposure compared to non‐vaccinated patients.ConclusionThere is a high seroprevalence of HBV in children with malignancies in Sudan. Vaccination appears to play a major protective role. Pediatr Blood Cancer 2015; 9999:1–3 © 2015 Wiley Periodicals, Inc.