The principles of combination chemotherapy to overcome drug resistance and the use of high intermittent dosage to achieve maximal therapeutic benefits, first learned from studies in childhood acute lymphocytic leukemia, were applied to other hematologic malignancies and to solid tumors. As new drugs that were active against specific malignancies became available, they were tested in combination with other agents. Drugs with different mechanisms of action and no overlapping toxicity were preferentially selected for combination chemotherapy. Cures were achieved in Hodgkin’s disease, testicular cancer and Burkitt’s lymphoma, as well as improved survival in non-Hodgkin’s lymphomas. These major successes occurred in tumors characterized by a relatively rapid proliferating growth rates and were not paralleled by similar results in cancers with slower growth rates.