The nutritional sequelae of neuroblastoma are secondary to tumor burden, tumor-host influenced metabolism, and antitumor operative, pharmacologic, and radiation therapy. Nutritional support and its influence on the outcome of clinical cancer is confusing; but in a defined murine system, we hypothesized that whether or not nutritional repletion favors the host-tumor relationship is dependent on a nutritional augmentation of host antitumor immunity. C1300 murine neuroblastoma (NB) elicits a host antitumor immune response as determined by in vivo and in vitro testing; but the TBJ clone of the same tumor is nonimmunogenic. After receiving two weeks of either regular 24% protein or protein restricted 2.5% protein chow, normal and malnourished mice received either C1300-NB or TBJ-NB and were serially followed to animal death. The median survival time (MST) of TBJ recipients was shorter in this more aggressive tumor, but the MST of 27.5 days was equal for normal and malnourished mice. Contrasting with these data were an MST of 38 days for malnourished C1300 NB recipients and an MST of 64.5 days for normally nourished C1300 NB recipients, values that are significantly different (P less than 0.02). These data suggest that nutritional support influencing host antitumor immunity may be of benefit only in that circumstance where the tumor elicits an antitumor immune response.