Background: The participation of nurses and midwives in vaginal birth care is limited in Brazil, and there are no national data regarding their involvement. The goal was to describe the participation of nurses and nurse-midwives in childbirth care in Brazil in the years 2011 and 2012, and to analyze the association between hospitals with nurses and nurse-midwives in labor and birth care and the use of good practices, and their influence in the reduction of unnecessary interventions, including cesarean sections. Methods: Birth in Brazil is a national, population-based study consisting of 23,894 postpartum women, carried out in the period between February 2011 and October 2012, in 266 healthcare settings. The study included all vaginal births involving physicians or nurses/nurse-midwives. A logistic regression model was used to examine the association between the implementation of good practices and suitable interventions during labor and birth, and whether care was a physician or a nurse/nurse-midwife led care. We developed another model to assess the association between the use of obstetric interventions during labor and birth to the personnel responsible for the care of the patient, comparing hospitals with decisions revolving exclusively around a physician to those that also included nurses/nurse-midwives as responsible for vaginal births. Results 16.2 % of vaginal births were assisted by a nurse/nurse-midwife. Good practices were significantly more frequent in those births assisted by nurses/nurse-midwives (ad lib. diet, mobility during labor, non-pharmacological means of pain relief, and use of a partograph), while some interventions were less frequently used (anesthesia, lithotomy position, uterine fundal pressure and episiotomy). In maternity wards that included a nurse/nurse-midwife in labour and birth care, the incidence of cesarean section was lower. Conclusions: The results of this study illustrate the potential benefit of collaborative work between physicians and nurses/nurse-midwives in labor and birth care. The adoption of good practices in managing labor and birth could be the first step toward more effective obstetric and midwifery care in Brazil. It may be easier to introduce new approaches rather than to eliminate old ones, which may explain why the reduction of unnecessary interventions during labor and birth was less pronounced than the adoption of new practices.