The nutritional and immunological status of 140 malnourished cancer patients who were to receive intravenous hyperalimentation (IVH) were evaluated prior to treatment with IVH and chemotherapy (CMX), surgery or radiation therapy (XRT). Subsequently, these indices were correlated with responses to treatment. Cell-mediated immunocompetent (CMI+) patients (41%) had lost an average weight of 10 +/- 2.2 lbs., while cell-mediated immunoincompetent (CMI-) patients (59%) had lost an average weight of 31 +/- 2.5 lbs. (p less that 0.05). Total lymphocyte count (TLC) averaged 1290 +/- 250 cells/mm3 in CMI+ patients and 900 +/- 140 cells/mm" in CMI- patients (p less than 0.05). Serum albumin concentration (SA) was 3.6 +/- 0.06 g/dl in CMI+ patients and 3.3 +/- 0.05 g/dl in CMI- patients (p less than 0.05). In the CMI+ group, 49% had a positive response to CMX, whereas only 27% of the CMI-group responded to CMX (p less than 0.01). In the surgery group, 88% of the CMI+ patients, but only 65% of CMI- patients, had uncomplicated postoperative recovery periods. Although nutritional repletion with IVH was undertaken in all patients, those patients with initial CMI- responses had greater body weight loss, lower SA and TLC and either a decreased response to CMX or an increase in postoperative morbidity and mortality when compared with patients who initially had CMI+ responses.