Background: Patients with advanced stages of head and neck cancer are often characterized by malnutrition and by an impaired immune system. Because some of the suppressed immune parameters were shown to be of prognostic importance in trauma and sepsis, we investigated whether these would also correlate with survival in head and neck cancer. Methods: Severely malnourished head and neck cancer patients undergoing ablative and reconstructive surgery were followed prospectively and their perioperative immune parameters were related to long-term survival. Results: Forty-nine patients with a preoperative weight loss of more than 10% were followed up for a period of at least 16 months after surgery. Analyses of variance revealed that preoperative human leukocyte antigen-DR (HLA-DR) expression on monocytes and endotoxin-induced production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were different between patients who survived and patients who died. Proportional hazards identified a weight loss of more than 12%, the presence of coexistent disease, and an HLA-DR expression on monocytes below the cutoff points (mean fluorescence index < 15, peak channel index < 9) to be of significant influence on survival. Conclusions: In addition to known prognostic parameters such as tumor stage, coexistent disease, and weight loss, the immune parameters HLA-DR expression on monocytes and endotoxin-induced cytokine production may carry prognostic value in cancer patients. Immunomodulating therapies leading to improvement of these parameters might in the future lead to increased options for treatment.