Potential pretreatment prognostic variables for patients presenting with liver metastases at the time of resection of primary colorectal cancers were evaluated in 42 consecutive patients resected over two years. Survival was bimodal with 12 patients dead within 6 months of surgery and the remaining patients dead or alive at follow-up at 6 to 27 months (median 9 months). Preoperative peripheral lymphocytes (P = 0.0008), alkaline phosphatase (P = 0.0056), and serum glutamic oxaloacetic and pyruvic transaminases (SGOT, P = 0.0048, and SGPT, P = 0.0031) were significant prognostic factors. The transaminases were prognostic within the normal ranges for the hospital laboratory. Age, sex, hematocrit, platelet count, bilirubin, cholesterol, albumin, protein, creatinine, tumor differentiation, bowel penetration, nodal involvement, operative blood loss, transfusions and chemotherapy were not related to survival. These results indicate that normal liver function tests in patients with colorectal liver metastases have significant prognostic value. Immune function as reflected by lymphocyte count may also play a role in these patients' survivals.