Introduction and hypothesis: The objective of this study was to compare the functional outcomes after pessary treatment and after prolapse surgery as primary treatments for pelvic organ prolapse (POP). Methods: This was a prospective cohort study performed in a Dutch teaching hospital in women with symptomatic POP of stage II or higher requiring treatment. Patients were treated according to their preference with a pessary or prolapse surgery. The primary endpoint was disease-specific quality of life at 12 months follow-up according to the prolapse domain of the Urogenital Distress Inventory (UDI) questionnaire. Secondary outcomes included adverse events and additional interventions. To show a difference of ten points in the primary outcome, we needed to randomize 80 women (power 80%, α 0.05, taking 10% attrition into account). Results: We included 113 women (74 in the pessary group, 39 in the surgery group). After 12 months, the median prolapse domain score was 0 (10th to 90th percentile 0–33) in the pessary group and 0 (10th to 90th percentile 0–0) in the surgery group (p OpenSPiltSPi 0.01). Differences in other domain scores were not statistically significant. In the pessary group, 28% (21/74) of the women had a surgical intervention versus 3% (1/39) reoperations in the surgery group (p = 0.01). Conclusions: In women with POP of stage II or higher undergoing surgery, prolapse symptoms were less severe than in those who were treated with a pessary, but 72% of women who were treated with a pessary did not opt for surgery. Trial registration number: Dutch trial register NTR2856.