OBJECTIVE To evaluate the frequency of different modes of delivery after one previous cesarean section and those factors which may influence mode of delivery. METHODS During the study period (1.1.2001-31.12.2005) 925 women with a previous cesarean section and a following singleton pregnancy were identified and included. Information regarding mode of delivery, induction of labor, instrumental delivery, the urgency and indications for first and second cesarean section, birth weight and Apgar scores were collected retrospectively. RESULTS Trial of labor (TOL) was initiated for 564 women of which 61% were successful while 39% delivered by an emergent cesarean section. In total, 346 women delivered vaginally (37%), 341 women (37%) delivered with an elective cesarean section and 238 (26%) underwent an emergency cesarean section. The VBAC rate increased during the study period, from 35% to 46%. Women who underwent an elective cesarean section due to fetal malpresentation (most often breech) in their first pregnancy were significantly more likely to have a successful VBAC in their second pregnancy (53%) compared with women who had an elective cesarean section for any other indication (21%) (p<0.0001). Uterine rupture occurred in six women (1%) during TOL, five underwent an emergency cesarean section and had healthy infants while there was one intrapartum fetal death. No correlation was found between birth mode and Apgar scores at five minutes. Perinatal mortality rate was 5,4 per thousand. Trial of labor was less likely to succeed if the infant's birth weight was >4000 grams compared with <4000 grams (p<0.01). CONCLUSIONS The results of this study indicate that VBAC is a safe option for women with a history of one previous cesarean section while in the hospital setting where there are resources for an immediate cesarean section. BACKGROUND Vaginal birth after cesarean section (VBAC), uterine rupture, perinatal mortality rate. Correspondence: Hildur Hardardóttir, hhard@landspitali.is.