The records of 121 patients with obstructing cancer of the colon were reviewed. About one-third of the patients had metastatic disease at the time of operation. Primary resection and anastomosis of the intestine was performed for most cancers of the ascending or transverse colon. Hartmann's procedure was performed in most patients with cancer of the sigmoid colon and rectum. Wound infection occurred in 20 patients (16.5%) and anastomotic leakage in six (4.9%). The operative mortality rate was 14.9%. The 5-year survival rate was 13.5%. Acute colonic obstruction is associated with high morbidity and mortality. The high incidence of advanced disease, advanced age, delay in tumour excision and unprepared bowel are some of the factors resulting in the poor prognosis of these patients.