Selective screening and partner notification are two principal means of preventing and controlling syphilis in the United States, yet few studies have been undertaken to compare and evaluate the cost or effectiveness of detecting syphilis using either strategy. The objective of this paper is to assess from the perspective of a health department the cost-effectiveness of selective screening compared with the strategy of partner notification in the detection of early syphilis in Houston, Texas, in 1994 and 1995. The cost-effectiveness analysis was performed using the recurring direct costs associated with detecting syphilis by both strategies. The middle estimates for the total direct costs associated with selective screening and partner notification were $579,101 and $229,529, respectively, for the 1466 and the 567 cases of early syphilis detected. On a cost per case basis, selective screening was more cost-effective than partner notification in the detection of primary, secondary and maternal syphilis cases. However, when consideration was given to prophylactic treatment, partner notification was more cost-effective in the detection of all early stage disease. Our findings suggest that the relative benefit of partner notification over selective screening depends on prophylactic treatment and an increase in worker productivity.