Little information is available concerning influenza immunization in patients with malignancies receiving chemotherapy. A large number of ambulatory patients are receiving chemotherapy for metastatic disease as well as adjuvant chemotherapy for microscopic disease, and they should be considered at higher risk for complications should they contract influenza. Seventeen oncology patients and 15 control subjects were given bivalent influenza vaccine (A/NJ/76-A/Vic/75) and their serologic responses were monitored. Although their responses were less than controls, nearly 50% of the oncology patients had a greater than fourfold rise in antibody titer, suggesting that a humoral antibody response could be achieved in spite of their underlying disease and immunosuppressive chemotherapy. No adverse reactions or deterioration of patient's clinical status were noted with vaccination. We conclude that significant antibody titer responses can be achieved in this population of patients.