This study examines the use of episiotomy and the frequency of perineal lacerations in a primary care maternity center staffed by certified nurse midwives (Booth Maternity Center) and a tertiary care teaching hospital where deliveries were performed by physicians (Thomas Jefferson University Hospital). The study sample (1262 women) was a stratified random selection of singleton live births in 1977 and 1978 at Booth Maternity Center and Thomas Jefferson University Hospital, with the demographic characteristics of women at Booth Maternity Center used as the sampling frame. Data were abstracted from medical records. Clinical and demographic factors that might be associated with the likelihood of having an episiotomy or experiencing a perineal laceration were examined using logistic regression. After controlling for other significant factors, women at Thomas Jefferson University Hospital were twice as likely to have an episiotomy as women at Booth Maternity Center. Use of an episiotomy was associated with a decrease in perineal lacerations of first- or second-degree, but a fourfold increase in the incidence of third-degree lacerations.