Aim: To examine the association between semi-sitting and sitting position at the time of birth and perineal damage amongst low-risk women in primary care. Background: Evidence on the association between birthing positions and perineal trauma is not conclusive. Most studies did not distinguish between positions during the second stage of labour and position at the time of birth. Therefore, although birthing positions do not seem to affect the overall perineal trauma rate, an increase in trauma with upright position for birthing cannot be ruled out. Methods: Secondary analysis was performed on data from a large trial. This trial was conducted amongst primary care midwifery practices in the Netherlands. A total of 1646 women were included who had a spontaneous, vaginal delivery. Perineal outcomes were compared between women in recumbent, semi-sitting and sitting position. Logistic regression analysis was used to examine the effects of these positions after controlling for other factors. Findings: No significant differences were found in intact perineum rates between the position groups. Women in sitting position were less likely to have an episiotomy and more likely to have a perineal tear than women in recumbent position. After controlling for other factors, the odds ratios (OR) were 0.29 [95% confidence interval (CI): 0.16-0.54] and 1.83 (95% CI: 1.22-2.73) respectively. Women in semi-sitting position were more likely to have a labial tear than women in recumbent position (OR: 1.43, 95% CI: 1.00-2.04). Conclusion: A semi-sitting or sitting birthing position does not need to be discouraged to prevent perineal damage. Women should be encouraged to use positions that are most comfortable to them. © 2010 Blackwell Publishing Ltd.