We have reviewed the therapeutic effects of benzodiazepines employed as adjuncts to cancer treatment. These agents have been used primarily for alleviating or attenuating situational anxiety, insomnia, chemotherapy-induced nausea and vomiting, and anticipatory nausea and vomiting. Situational anxiety not corrected by psychosocial support, symptom control, or time may be successfully treated with benzodiazepines. Procedure-related anxiety, for example, that related to bone marrow biopsy, venipuncture, intrathecal therapy, and the insertion of subclavian and femoral catheters, is a serious problem that may be alleviated by the use of benzodiazepines. Insomnia not caused by a depression serious enough to warrant treatment with a tricyclic antidepressant also may be successfully treated with benzodiazepines. Many clinicians have found benzodiazepines to be useful adjuncts to a cancer chemotherapy regimen because of their anxiolytic, sedative, and amnesic properties and also because of their suspected antiemetic properties when these drugs are used in conjunction with known antiemetic agents. The ability of lorazepam to induce antegrade amnesia has proved particularly useful in alleviating anticipatory nausea and vomiting connected with repeated courses of cytotoxic chemotherapy. Furthermore, since benzodiazepines are relatively safe drugs, their continued and probably expanded uses as cancer therapy adjuncts can be anticipated.