OBJECTIVE To estimate the risk of prolapse associated with levator avulsion injury among a urogynaecological clinic population. METHODS Retrospective observational study. METHODS Tertiary urogynaecological unit. METHODS A total of 934 women seen for interview, examination using the pelvic organ prolapse quantification (POP-Q) staging system and imaging of the levator ani muscle by four-dimensional translabial ultrasound. METHODS Retrospective review of charts and stored imaging data. METHODS Pelvic organ prolapse stage II and higher and presence of defects of the levator ani muscle. RESULTS After exclusion of 137 women with a history of anti-incontinence or prolapse surgery, and a further exclusion of 16 women in whom either examination or imaging was impossible, we compared prolapse and imaging data in 781 women. Mean age was 53 years (range 15-89 years), and median parity was 2 (range 0-12). Women reported stress incontinence (76%), urge incontinence (69%), frequency (47%), nocturia (49%) and symptoms of prolapse (38%). Significant prolapse (stage II or higher) was diagnosed in 415 (53%) women, and 181 (23%) women were found to have levator avulsion defects. Prolapse was seen in 150/181 (83%) women with avulsion and in 265/600 (44%) women without avulsion, giving a relative risk (RR) of 1.9 (95% CI 1.7-2.1). The association was strongest for cystocele (RR 2.3, 95% CI 2.0-2.7) and uterine prolapse (RR 4.0, 95% CI 2.5-6.5). CONCLUSIONS Women with levator avulsion defects were about twice as likely to show pelvic organ prolapse of stage II or higher than those without. This effect is mainly due to an increased risk of cystocele and uterine prolapse.