This paper reports on a 3-month longitudinal study comparing the crying behavior of a group of babies delivered by the "nonviolent" Leboyer method with a control group delivered by traditional methods. Subjects were 24 white, middle class infants delivered by minimally medicated, multiparous and primiparous mothers. Fourteen newborns were "Leboyer babies," meaning they were delivered in quiet, dimly lit rooms and immersed in a warm bath soon after delivery. Remaining infants had conventional births--bright lights, normal conversation and no bath. Assignment to groups was based upon parental decision. In the delivery room Leboyer newborns cried slightly more frequently for a greater duration of time (29% versus 23%) than did the control group. There was no difference in intensity of cry. The greatest differences were in parental behaviors, with Leboyer parents more involved in the whole delivery process. Wake/sleep diaries and two 2-hour home observations when infants were three months old revealed few differences. Mother's reports on Rothbart's Infant Behavior Questionnaire showed no significant differences. Some "typically" Leboyer behaviors were observed in delivery rooms. Two infants smiled; one did so 5 times in apparent response to parental overtures. While not significant, Leboyer babies opened their eyes in half the time it took control infants. More accurate duplication of Leboyer's method is needed. (Author/RH)