Pelvic organ prolapse is a common problem that adversely affects the daily activities and quality of life of many women. Pelvic floor muscle training interventions are commonly used by physiotherapists to manage prolapse. However, a Cochrane review found limited evidence to support the effectiveness of such interventions. Based on the findings of a successful feasibility study, this multi-centre randomised controlled trial will address the paucity of evidence. 556 symptomatic women with diagnosed prolapse will be enrolled in 16 UK centres and 1 New Zealand centre over 16 months and randomised to pelvic floor muscle training plus lifestyle advice, or to receive a lifestyle leaflet only. Principal measures of outcome are: prolapse symptoms, prolapse severity, and subsequent further treatment up to 12 months after trial entry.