We standardized an indirect ELISA for measurement of serum antibody levels to four individual treponemal recombinant proteins that have been commonly used in a number of commercial EIAs, mostly as a mixture of antigens. When tested with 127 syphilis-negative and 37 secondary syphilis sera, ELISA O.D.s obtained for each of the four antigens clearly distinguished between these two groups of samples. Sensitivity and specificity of 100% was obtained with the current set of samples. Further evaluations with sera from different stages of syphilis can help to define the applications of this ELISA test for each of the four antigens studied.