Purpose: Risk factors for recurrence of rectal prolapse after surgery remain unclear. Delorme’s procedure is often selected for relatively small-sized rectal prolapse, but there are few reports discussing the association between prolapsed rectum length and prolapse recurrence after Delorme’s procedure. We hypothesized that patients with longer rectal prolapses are at a higher risk of recurrence after Delorme’s procedure. Methods: The study population comprised patients with rectal prolapse who underwent Delorme’s procedure between January 2014 and December 2019 at Tokyo Yamate Medical Center. We extracted data on patient age, sex, body mass index, previous history of anal surgery, previous history of surgery for rectal prolapse, and length of prolapse, to identify risk factors for prolapse recurrence. Results: Altogether, 96 patients were eligible for analysis. The median length of the prolapsed rectum was 3.0 cm (range, 1.0–6.6 cm). Twenty-four patients (25.0%) experienced recurrence after Delorme’s procedure after a median of 7.5 months (interquartile range, 3.2–20.9 months). Multivariate analysis revealed that longer prolapsed rectum length increased the risk of recurrence after Delorme’s procedure (hazard ratio, 6.28; 95% confidence interval, 1.83–21.50; P<0.001). Conclusion The length of the prolapsed rectum should be measured before Delorme’s procedure for rectal prolapse, because length is associated with a risk of recurrence after the surgery.