The clinical courses of 68 patients with obstructive colonic cancers were reviewed. For the majority of patients with an acutely obstructing cancer of the left colon a conventional staged procedure remains the most appropriate treatment. Primary resection is suitable for the more proximal colonic cancer with obstruction. The operative mortality rate was 13.6 per cent, but with the addition of two nonoperative deaths, the figure rises to 16.2 per cent. Only six patients are known to have survived five years.