The impact of different immunization strategies on hepatitis B infection rates in Italy over a 20 year period is simulated by the means of a simple deterministic mathematical model. The anticipated effect of vaccination of health workers only, of newborns from HBsAg+ mothers, of all newborns, of the entire population are simulated. Immunization of newborns from HBsAg+ mothers is by far the strategy with the greater effectiveness per unit cost.