Background: Laparoscopy has revolutionized many abdominal surgical procedures. Laparoscopic colectomy has become increasingly popular. The short- and long-term benefits and satisfactory surgical oncological treatment of colorectal cancer by laparoscopic-assisted resection remain topical. The long-term outcomes of all international randomized controlled trials are still awaited, and short-term outcomes are important in the interim. Methods: Between January 1998 and April 2005, a multicenter, prospective, randomized clinical trial in patients with colon cancer was conducted. Six hundred and one eligible patients were recruited by 33 surgeons from 31 Australian and New Zealand centers. Patients were allocated to colectomy by either laparoscopic-assisted surgery (n = 294) or open surgery (n = 298). Patient demographics and secondary end-points, such as operative and postoperative complications, length of hospital stay, and histopathological data, will be presented in this article. Analysis was by intention-to-treat. Survival will be reported only as the study matures. Results: Histopathological parameters were similar between the two groups, except in regard to distal resection margins. There was no statistically significant difference found in postoperative complications, reoperation rate, or perioperative mortality. Statistically significant differences in quicker return of gastrointestinal function and shorter hospital stay were identified in favor of laparoscopic-assisted resection. A statistically significant increased rate of infective complications was seen in cases converted from laparoscopic-assisted to open procedures but with no difference in reoperation or in-hospital mortality. Conclusions: Laparoscopic-assisted colonic resection gives significant improvements in return of gastrointestinal function and length of stay, with an increased operative time and no difference in the postoperative complication rate.