A new staging system for intermediate grade lymphomas and immunoblastic lymphomas is described. This system is based on the tumor score which consists of assigning a point to each one of five variables that have been previously shown to have a high prognostic value. Ann Arbor stages III-IV, presence of bulky mass, elevation of B-2 microglobulin and LDH as well as presence of 'B' symptoms are the variables utilized in this system. When we applied this tumor score system to a population of 144 patients uniformly treated with CHOP/Bleo/CMED protocol, we observed that this system can accurately divide the population into two prognostic groups without an intermediate category. The first group is made up of those patients with a score of 0-2 points while the second group consists of patients with a score of > or = 3 points. The first group has a time-to-treatment failure (TTF) of 83% at three years in contrast to the second group whose TTF was 24%. If we compare this system with other commonly used systems in our institution, such as Ann Arbor, M.D. Anderson clinical staging system, and M.D. Anderson serological staging system, we observed that the tumor score system is not only more specific and sensitive than the others but also was capable of eliminating an intermediate risk group, thus facilitating therapeutic choices. This tumor score system is easy to apply and potentially reproducible in any institution.