Retrospective analysis of 256 medical records of children with confirmed diagnosis of hepatitis B virus infection was done. The study focused on significance of patient's age and sex in the course of the disease, on circumstance accompanying the HBV infection and on course of infection, especially a chronic HBV infection. It has been found that factors increasing the risk of infection include: former hospitalizations, surgical procedures, malfunctions of an immune system and familial contacts. Hepatitis occurred more frequently in infants and young children and in this age it more often converted into a chronic form. The course of hepatitis infection depended on dynamics of the disease process. Seroconversion occurred more often after acute phase of the disease and asymptomatic course of infection most often resulted in chronic form. Treatment with immuno-potent (TFX, isoprinosine) had no effect on the course of hepatitis B infection. It should be recommended to extend prophylaxis to children of the risk group and to introduce routine test for HBs antigen in each inpatient child.