Benefit-cost analysis was applied to a model of first-trimester screening for syphilis where approximately ten new cases of early infections are identified and treated per 50,000 pregnancies. The cost of the screening is estimated to be +4.60 (U. S.) per participating woman, while the benefit-cost ratio was 3.8; thus the economic benefits are nearly four times the cost of the program. Furthermore, there are many other beneficial factors that cannot be evaluated in terms of money. The validity of the results varies with discount rates, frequencies of syphilitic infection, and rates of transmission to the fetus. If the incidence of maternal syphilis is 0.005%, the benefits equal the costs of the prevention program. In Norway, prenatal screening has been obligatory for 30 years. This represents a net benefit, or a total savings, of +8.6 million (U. S.; 1979). From an economic point of view, the first-trimester serologic screening should continue unabridged, whereas an extended preventive program, including premarital screening or additional third-trimester serologic tests, may not be advisable in Norway.