One hundred patients with chronic lymphocytic leukemia (CLL) followed in our department between November 1969 and December 1982 were reviewed and classified according to the staging system proposed by the International Workshop on CLL (IWCLL). Analysis of actuarial survival curves revealed a significant chi-square value for heterogeneity and trend. In addition, thrombocytopenia and anemia appeared to be the most important risk factors. A large variability in the course of disease, not well explained by the staging system of the IWCLL, was found among the nonanemic and nonthrombopenic patients. Analysis of A and B stage patients according to absolute peripheral blood lymphocytosis (less or more than 50 X 10(9)/liter) showed two separate patterns of survival.