Introduction and hypothesis The objective of our study was to describe the distribution of pelvic organ prolapse (POP) in a population of women undergoing POP reconstructive surgery and to identify compartment-specific risk factors. Methods We conducted a retrospective observational study in a cohort of 326 women who underwent POP repair and had a standardized preoperative POP assessment using the Baden-Walker classification. The distribution of POP grade was described for each vaginal compartment. The association between the involvement of each specific compartment and predictors was evaluated with a logistic regression model. Results The frequency of significant POP (grade ≥ 2) was 79% in the anterior compartment, 49% in the middle/apical compartment and 31% in the posterior compartment. Combined significant anterior and apical defects were present in 25% of women. Increasing age was a significant risk factor for apical defect (between 60 and 70 years OR = 2.4, 95% CI 1.2–4.6; > 70 years OR = 3.4, 95% CI 1.7–6.6). Previous hysterectomy (OR = 2.2, 95% CI 1.0–4.6) was a significant risk factor for posterior defect. Conclusions In a population undergoing POP surgery, anterior compartment involvement is the most common and serious defect and can often be associated with an apical defect, especially in older women. In case of previous hysterectomy, the posterior compartment may be weakened. These findings may help surgeons to select the appropriate POP reconstructive surgery, which often should address both anterior and apical defects.