In October 1999, CDC, in collaboration with other federal partners, launched the National Plan to Eliminate Syphilis in the United States. In 1998, Congress initiated funding for the syphilis elimination effort. Syphilis elimination is defined as the absence of sustained transmission (i.e., no transmission after 90 days of the report of an imported index case). The national goal for syphilis elimination is to reduce primary and secondary (P&S) syphilis to <1000 cases (rate: 0.4 per 100,000 population) and to increase the number of syphilis-free counties to 90% by 2005. To describe the epidemiology of syphilis in the United States, CDC analyzed notifiable disease surveillance data for 1999. This report summarizes the results of that analysis, which indicate that, in 1999, P&S syphilis declined to a rate of 2.5 cases per 100,000 population, the lowest rate ever reported, and that syphilis transmission increasingly is concentrated in a few geographic areas.