Between 1985 and 1990, 517 patients were treated for colorectal malignancies at our department of surgery. Nd:YAG laser therapy was used in 37 cases (7.1%). The mean age of these 22 men and 15 women was 71.4 years (range: 22-96 years). One hundred-twenty-nine Nd:YAG laser treatments were performed. Indications for laser treatment were (1) palliative tumor reduction (n = 21), (2) preresectional laser recanalization for obstructing carcinoma (n = 6), and (3) curative treatment (n = 10). Laser related complications included one perforation of the rectum and one rectovaginal fistula. One fatal pulmonary embolism occurred. After palliative treatment, five patients died because of tumor progression (mean survival time: 16 months), two because of other reasons. All patients with obstructing tumors could be recanalized successfully. After curative treatment, eight patients are still alive without tumor recurrence (mean survival time: 25.5 months), and two died of other causes. Palliative Nd:YAG laser treatment of colorectal malignancies is a competitive alternative to conventional surgery. Recanalization of obstructing tumors is an excellent treatment for large bowel obstruction, making one-stage resections possible. Curative treatment should be reserved for special cases only.