Background: Open colorectal surgery (CRS) leads to high rates of adhesive small bowel obstruction (SBO) and incisional hernia development with large clinical impact and financial burden. In this study we evaluated the cumulative incidence of access related complications in a cohort of patients who underwent open and laparoscopic CRS. Methods: We reviewed cases of elective or emergency CRS patients kept prospectively on a database and examined annually. Case notes were studied for adhesive SBO episodes requiring admission or reintervention. Development of incisional hernia with or without repair was also recorded. The diagnosis of SBO was defined by a combination of clinical criteria and imaging. Time interval of SBO, surgery type and setting, readmission length and findings at reintervention were recorded. Patients undergoing CRS for inflammatory bowel disease, patients with peritoneal carcinosis, or patients with SBO secondary to local or peritoneal recurrence during the follow-up were excluded. Patients who underwent other abdominal surgery during the follow-up were also excluded. Data were analysed using Mann-Whitney U test and chi-square test. The Kaplan Meier method was used for cumulative probability of developing SBO. Results: from 1/03 to 11/08, 527 patients satisfied our criteria and underwent elective (84.8%) or emergency (15.2%) CRS (83.3% open and 16.7% laparoscopic). Median follow-up was 27 months (range 0.2-71.8). Thirty-two patients (6.1%) experienced 54 SBO episodes and 8 required surgery (1.5%). There was a large variation in the time of first SBO occurrence, 56.3% occurred within 3 months, 21.9% between 3 and 12 months and 21.8% after 1 year. The risk of surgery at first admission for SBO was 25% and the number of readmissions predicted the need of surgery. The risk of reoperation was greatest during the first year after CRS and steadily rised every year thereafter.SBO was higher after pelvic surgery or extensive resections compared to minor procedures (6.6% vs 2.9%). Likewise, SBO risk was higher after emergency compared to elective surgery (1.3% vs 6.9%), but similar after open compared to laparoscopic surgery (6.2% vs 5.7%). Any previous or additional surgery raised the overall risk of SBO from 5.3% to 12.3%. Incisional hernia development was similar between open and laparoscopic surgery (3.4% vs 1.6%). Conclusions: Colorectal surgery results in significant ongoing risk of SBO according to the colorectal procedure. This risk seems to be similar between laparoscopic and open approach, higher after emergency surgery and for patiens with previous surgery. The number of readmissions for SBO predicts the need of surgery.