The aim of this study was to prospectively assess the results of our first 100 consecutive patients who underwent laparoscopic or laparoscopy-assisted colorectal operations. The parameters studied included the type and length of procedure, intra- and postoperative complications, conversion to open surgery, length of ileus, and hospitalization. A total of 100 laparoscopic and laparoscopy-assisted procedures were performed between May 1991 and April 1994. The mean patient age was 49 years (12-88 years). The procedures included 36 total abdominal colectomies (TACs) (ileoanal reservoir 28, ileorectal anastomosis 6, end-ileostomy 2), 39 segmental resections of the colon and small bowel, 8 resections of the rectum, 7 diverting stoma creations, 7 reversals of Hartmann's procedure, and 3 other procedures. In seven cases (7%) the laparoscopic procedure was converted to a laparotomy. A group of 22 patients sustained 26 complications that included enterostomy (n = 5), hemorrhage (n = 6), intraabdominal abscess (n = 4), prolonged ileus (n = 4), wound infection (n = 2), anastomotic leak (n = 1), aspiration (n = 1), cardiac arrhythmia (n = 1), upper intestinal bleeding (n = 1), and postoperative small bowel obstruction (n = 1). There were no deaths. When divided into three equal, consecutive groups, the patients in the early (n = 33) and intermediate (n = 33) groups had a significantly higher complication rate (42% and 27%, respectively), than those in the late group (n = 34, 12%;p < 0.05). The complication rate in each group was also directly related to the number of TACs performed (18 in the early, 13 in the intermediate, and 5 in the late group). The overall complication rate in TAC cases was significantly higher (42%) when compared to that of all other procedures (segmental resection 9%, nonresectional 12%;p < 0.01). The mean operating time was 4 hours (2.5-6.5 hours) for TAC, 2.5 hours (1.5-5.5 hours) for segmental colonic resection, and 1.6 hours (1.0-2.5 hours) for the nonresectional procedures. The length of ileus was 3.5 days (2-7 days) after TAC, 3 days (2-7 days) after the segmental resections, and 2 days (1-4 days) after the nonresectional procedures. The mean hospital stay was 7.3 days (2-40 days): 8.4 (5-40), 7.0 (4-12), and 6.8 (2-11) days for the TAC, segmental resection, and nonresectional procedures, respectively. We conclude that the feasibility of laparoscopic colorectal surgery has been well established. The morbidity associated with laparoscopic colorectal surgery correlates with a steep learning curve but is also related to the type of procedure. TAC is associated with a higher complication rate than are other laparoscopic colorectal procedures.