Presently, the diagnosis of syphilis is dependent mainly on serological tests. The most widely used screening tests for syphilis are the VDRL and the rapid plasma reagin (RPR) and for confirmation, the fluorescent treponemal antibody (FTA) and the treponema pallidum hemagglutination (TPHA) tests. The four alternative modes for diagnosis of syphilis can be a) VDRL + FTA, b) VDRL + TPHA, c) RPR + FTA and d) RPR + TPHA. Here the author reports an evaluation of cost utility of these tests in medical practice. It is shown that the cost per accurate diagnosis with VDRL + TPH is the least expensive choice. Therefore, this alternative is the best method for serological diagnosis for syphilis, based on medical laboratory economics principles