The data from 1050 patients who had undergone colorectal carcinoma resection at the University of Cologne between 1976 and 1990 were studied. The aim of the study was to determine the concomitant effects on survival of several patient characteristics (sex, age, tumour localization, blood transfusion) and histopathological variables (Dukes' staging). We first calculated survival rates, both including and excluding post-operative mortality. We set up a hierarchical log-linear model for the detection of relationships between selected crossclassified categorial variables. We then used Cox's proportional hazard regression method to study the relationship between survival and different prognostic patterns. Dukes' staging was shown to be a highly discriminating factor in survival (P < 0.001). Survival rates were better in women (P < 0.001), and better for younger patients (< 70 years; P < 0.001). Tumour site (colon; P = 0.0362) and blood transfusion(P = 0.0857) also correlated with survival.