Purpose Sigmoid resection for diverticular disease is a frequent surgical procedure in the Western world. However, long-term bowel function after sigmoid resection has been poorly described in the literature. This study aims to assess the long-term bowel function after tubular sigmoid resection with preservation of inferior mesenteric artery (IMA) for diverticular disease. Methods We retrospectively identified patients who underwent sigmoid resection for diverticular disease between 2002 and 2012 at a tertiary referral center in northern Germany. Using well-validated questionnaires, bowel function was assessed for fecal urgency, incontinence, and obstructed defecation. The presence of bowel dysfunction was compared to baseline characteristics and perioperative outcome. Results Two hundred and thirty-eight patients with a mean age of 59.2 ± 10 years responded to our survey. The follow-up was conducted 117 ± 32 months after surgery. At follow-up, 44 patients (18.5%) had minor LARS (LARS 21–29) and 35 (15.1%) major LARS (LARS ≥ 30–42), 35 patients had moderate-severe incontinence (CCIS ≥ 7), and 2 patients (1%) had overt obstipation (CCOS ≥ 15). The multivariate analysis showed that female gender was the only prognostic factor for long-term incontinence (CCIS ≥ 7), and ASA score was the only preoperative prognostic factor for the presence of major LARS at follow-up. Conclusion Sigmoid resection for diverticular disease can be associated with long-term bowel dysfunction, even with tubular dissection and preservation of IMA. These findings suggest intercolonic mechanisms of developing symptoms of bowel dysfunction after disruption of the colorectal continuity that are so far summarized as “sigmoidectomy syndrome.”