McCormack, W. M. (Channing Laboratory, Boston City Hospital, Boston, Mass. 02118), B. Rosner and Y-H. Lee. Colonization with genital mycoplasmas in women. Am J Epidemiol 97: 240–245, 1973.—Vaginal and urethral cultures for genital mycoplasmas (Mycoplasma hominis and T-mycoplasmas) were obtained from 570 women attending the Prenatal and Gynecology Clinics of the Boston City Hospital and from 187 patients seen in the private ofilces of seven obstetricians and gynecologists. Multiple regression analysis was used to relate mycoplasmal colonization to several variables. Colonization with both M. hominis and with T-myco-plasmas was more prevalent among patients who were seen at Boston City Hospital and among women who were taking oral contraceptives. In addition, M. hominis was more prevalent among black than among white women, and T-mycoplasmas were more prevalent among women who had never been married than among those who were or had been married.