Purpose: Colonic inertia (CI) may co-exist with obstructed defaecation (OD). It is unclear if it adversely influences the results of surgery for OD. We aimed to compare the functional results of laparoscopic anterior rectopexy (LAR) for OD secondary to high-grade internal rectal prolapse (IRP) in those with normal colonic transit (NCT) and CI. Methods: Patients with high-grade (recto-anal) IRP were evaluated with defaecating proctography and colonic transit study. Colonic transit time (CTT) (hours) was calculated by the number of pellets remaining in the colon and rectum at 7 days x 2.4. Patients were offered surgery for significant symptoms if they failed a program of conservative management. Constipation was prospectively assessed pre-op and at 3 months using Wexner constipation scores. Results: 80 patients (93% female) underwent LAR for OD and IRP. Patients with NCT gave less history of stool infrequency currently (10% versus 32%) and in their 20’s (17% versus 71%). 61 patients had normal colonic transit (CTT median 17, range 0-48 hours) and 19 had CI (CTT median 79, range 50-154 hours, p<0.0001). Overall symptom improvement at 3 months was similar for NCT and CI (84% versus 84%, p=0.97). Rates of total (50% versus 68%, p=0.19) and partial (34% versus 16%, p=0.16) symptom improvement were similar. Improvement in Wexner constipation score was similar for NCT (mean pre-op 13 to post-op 5) and CI (14 to 5), (p=0.34). Conclusions: In the short term, colonic inertia has no adverse impact and may be disregarded when considering laparoscopic anterior rectopexy for obstructed defaecation and high-grade internal rectal prolapse.