Objectives To study effects of physiotherapist-guided pelvic floor muscle training on pelvic organ prolapse (POP) early postpartum period. Design Assessor-blinded, randomized controlled trial. Setting Physiotherapy Clinic, Reykjavik. Sample Eighty-four primiparous women with a singleton delivery. Methods Participants were screened for eligibility 6-13 weeks postpartum. Women randomized to the training group conducted 12 weekly individual sessions with a physiotherapist, starting on average 9 weeks after childbirth. Outcomes were assessed after the last session (short-term) and at 12 months postpartum (long-term). The control group received no instructions after the initial assessment. Main outcome measures Self-evaluated POP symptoms by the Australian Pelvic Floor Questionnaire. Results Forty-one and 43 women were randomized to the training and control groups, respectively. At recruitment, 17 (42.5%) of the training and 15 (37%) of the control group reported prolapse symptoms (p=0.6). Five (13%) from the training and 9 (21%) controls were bothered by the symptoms (p=0.3). There was a gradual decrease in the number of women with symptoms and no significant short-term (p=0.08 at 6 months) or long-term (p=0.6 at 12 months) differences between the groups regarding rates of women with POP sympoms. No difference was between groups regarding bother in the short (p=0.3) or longer term (p=0.4). Repeated measure analyses using Proc Genmod in SAS did not indicate a significant effect of the intervention over time, p>0.05. Conclusions There was an overall decrease in postpartum symptoms of POP and bother during the first year. Physiotherapist-lead pelvic floor muscle training did not change the outcomes.