This research was conducted in a public general hospital in Mexico City, Mexico. The objective was to evaluate efficacy of the support given by a doula during labor to reduce cesarean rate. From March 1997 to February 1998, a group of 100 pregnant women were studied. These women were at term, engaged in an active phase of labor, exhibited 3 cm. or more cervical dilatation, were nuliparous, had no previous uterine incision, and possessed adequate pelvises. The group was randomly divided into two subgroups comprising 50 women, each: The first subgroup had the support of a childbirth educator trained as a doula, while the second subgroup did not have doula support. Measurements were recorded on the duration of labor, the use of pitocin, and whether or not the birth was a vaginal birth or cesarean section. Characteristics and gestational age were similar in both groups. Results confirmed that support by doulas during labor was associated with a significant reduction in cesarean birth and pitocin administration. There was a trend toward shorter labors and less use of epidurals. The results of this study showed, as in other trials measuring the impact of a doula's presence during labor and birth, that doula support during labor is associated with positive outcomes that have physical, emotional, and economic implications.