Evaluation of the effect of autologous blood injection into muscular layer on the immune system in children who were treated endoscopically for vesicoureteral reflux. There were 29 children examined after before and endoscopic autohemoinjection. The examination included determination of basic immunoglobulin levels in serum (IgA, IgG, IgM). Also the human lymphocyte subpopulations were determined. Initial and final values were compared, average values and standard deviations for respective age groups were determined. Autologous blood used for injections in endoscopic treatment of vesicoureteral reflux stimulates immune system, especially in young children.