Combinations of chemotherapeutic agents with various biological response modifiers (“biomodulators”) in the treatment of cancer are now being tested. Since most (though not all) chemotherapy is immunosuppressive, the schedules by which the chemotherapeutic agents and the biomodulators are combined are of critical importance. This review summarizes the effects of chemotherapy on immunity and suggests the most logical ways in which these categories of drugs might be combined with biomodulators. Specific examples are also provided of combination therapies that have proved useful or that are of significant potential utility. An understanding of the types of action and the mechanisms of action of specific chemotherapeutic agents and specific biomodulators may help to achieve additive effects (possibly synergism) with these combinations. At the very least, that understanding will avoid the hazard of one modality's negating the effects of the other. [J Natl Cancer last 1988;80:1445–1450