The problems of herpes simplex in gynecology and obstetrics are reviewed. There were 40 patients showing the characteristic cellular changes of herpetic infection among the 79,357 Papanicolaou smears taken. Four patients, with cytologic evidence of herpes virus, also had cervical dysplasia. The relationship between herpes virus and dysplasia, carcinoma in situ, and invasive carcinoma is discussed. The use of a properly timed Papanicolaou smear to alert the physician to the danger of an infected birth canal is described. Three cases of neonatal herpes are cited.