In an investigation of the indications for hepatic resection in the treatment of colorectal carcinoma metastases, the records of 859 patients who had undergone this procedure were reviewed. This patient group, from 24 institutions, was found to have a 5-year actuarial survival of 33% and a 5-year actuarial disease-free survival of 21%. The only factors that might by themselves be considered contraindications to hepatic resection are the presence of positive hepatic nodes, the presence of resectable extrahepatic metastases, or the presence of four or more metastases. Other factors that had a negative effect on long-term survival were margins of resection on the liver metastases less than or equal to 1 cm (S [5-year actuarial survival] = 23%), the presence of positive mesenteric nodes in the primary tumor specimen (S = 23%), and a disease-free interval of less than 1 year (S = 24%). The effect of any one of these factors was not great enough to contraindicate resection. However, combinations of prognostic factors must be considered before resection is recommended. The overall 5-year survival rate for this large series has been very satisfying. Decision making in the future must take into account such factors as number of metastases, extrahepatic involvement, and stage of the primary tumor.