In a prospective study, 88 women bathed in a warm tub bath for 1/2–2 hours during fist stage labor after a strictly normal pregnancy, ending with spontaneous onset of labor at term. A control group consisted of 72 women fulfilling the same criteria of normality during pregnancy and labor, but who did not want to take a warm tub bath during labor. Apart from the bath, the two groups followed the usual obstetric procedures of the Department. The cervical dilatation in the “bath group” was 2 1/2 cm/h compared with 1 1/4 cm/h in the “control group”. Mean pain score in the bath group was higher at the start of the study, before the bath, and they experienced a pain relief during bath which was not observed in the control group. This difference may be due to bias. The use of morfica and the need for stimulation of labor contractions were both twice as high in the control group, but this difference was not significant. No differences were observed with regard to operative delivery, vaginal or perineal laceration or in bleeding during labor or post-partum. The total duration of labor was the same in the two groups and no differences in neonatal condition were observed. The bacterial contamination of the bath water was insignificant and there were no significant febrile episodes post partum.