This chapter examines the role played by doctors in the regulation of prostitution and in containing the spread of venereal disease. At a time when, around the world, concern about, as well as research into, venereal disease were on the rise, doctors in Peru were drawn to its study. As they began to diagnose venereal disease more accurately, and came to recognize how it affected the Peruvian population, doctors grew increasingly anxious about the institutional capacities to properly treat venereal disease and what a high incidence of venereal disease signified for the nation. The creation in the 1910s of the Asistencia Pública, the institution charged with the medical inspection of prostitutes, and, in the 1920s, of the sifilicomio (syphilis clinic) did little to reduce the spread of venereal disease.