In 220 patients with advanced colorectal carcinoma, objective tumor response to chemotherapy and survival were related to the following parameters: age, sex, performance status, time interval from diagnosis to metastases, initial site of metastases, and initial white blood cell count, lactic dehydrogenase, alkaline phosphatase, and carcinoembryonic antigen levels. Each variable was first evaluated separately. By conventional statistical methods, none of the variables significantly predicted response, although the following parameters significantly (p less than 0.01) predicted survival: Patients with an initially normal level of lactic dehydrogenase versus those with an abnormal level of lactic dehydrogenase had median survivals of 16 and 7.0 months, respectively; normal versus abnormal carcinoembryonic antigen levels, 23 and 9.2 months, respectively; white blood cell count of less than 10,000 versus greater than 10,000 cells/mm3, 11 and 7.0 months, respectively; performance status of greater than 70 versus less than 60, 11 and 6.6 months, respectively; and lung versus liver metastases, 12 and 8.0 months, respectively. By studying the variables together with multivariate analysis, we found that the most important variables in predicting response were the lactic dehydrogenase level and the white blood cell count. In predicting survival, the most important variables were the lactic dehydrogenase level, performance status, and lung involvement. We recommend that future randomized therapeutic trials for advanced colorectal carcinoma should delineate and perhaps stratify for the lactic dehydrogenase level, performance status, white blood cell count, and/or the presence of lung involvement.