Background: To put statistically significant changes in patient reported outcome measurement (PROM) questionnaires into a clinical perspective, the concept of the minimal clinically important difference (MCID) can be used. Aim: To determine the MCID for the summary score for sexually active (SA) women of the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire, IUGA-Revised (PISQ-IR), a validated instrument which assesses sexual functioning (SF) for patients suffering from a symptomatic pelvic floor disorder. Methods: Patients participating in a multicentre prospective cohort study comparing pessary therapy with surgery for a symptomatic pelvic organ prolapse (POP) filled in the PISQ-IR at baseline and 12 months' follow-up. We used both an anchor-based as well as a distribution-based method to calculate the MCID for both treatment groups. The Patient Global Impression of Improvement (PGI-I) questionnaire and PISQ-IR question 19a about satisfaction with sexual functioning were used as anchors. For the distribution-based approach we used the effect size (ES). Outcomes: MCID for the SA summary score of the PISQ-IR.Results: Data of 243 women were used to calculate the MCID. In the pessary group, Kendall's tau-b correlation coefficients between the PISQ-IR summary score and both anchors were below the cut-off of 0.21, which implies the anchors cannot be used to calculate an MCID. In our surgery group, the PISQ-IR question 19a met the anchor criteria and 0.31 points increase in the PISQ-IR summary score was equal to an improvement of 1 point on question 19a about satisfaction with sexual functioning. Clinical implications: Future research on this subject should focus on clinical relevance of results rather than statistical significance only. Strengths & Limitations: Our main strength is the fact that we used both anchor-based and distribution-based methods to determine our MCID. Secondly, we set out to determine an MCID for both treatment groups separately, which relatively enhances the generalisability of our results. A limitation is that we were not able to estimate an MCID for the pessary group. Conclusion:We estimated the MCID for the PISQ-IR SA summary score to be 0.31 in our surgery group.