Levels of cytokines, and in particular those that reflect Th1 or Th2 bias, were measured in the plasma of patients with head and neck squamous cell carcinomas (HNSCC). Compared with plasma cytokine levels of age-matched controls, cytokine levels in HNSCC patients suggested a shift to a Th2 bias as levels of the Th2 cytokines interleukin-4 (IL-4), IL-6, and IL-10 were increased, and levels of the Th1 cytokine interferon-gamma (IFN-gamma) were decreased. However, levels of the Th1 cytokines IL-2 and granulocyte macrophage-colony-stimulating factor (GM-CSF) were increased, which is not consistent with full Th2 skewing. Assessment of cytokine levels in patients with malignancies other than HNSCC demonstrated many similarities to HNSCC patients, but HNSCC patients exhibited a more pronounced increase in GM-CSF levels and a decline in IFN-gamma levels. For most cytokines there was no association between the shifts in cytokine levels in HNSCC patients and either the extent of tumor burden or extent of metastasis. However, patients with large HNSCC tended to be the population that demonstrated increased levels of IL-4 and IL-6. These results suggest skewing toward a Th2 bias in HNSCC patients, with the Th2 shift being incomplete and indicative of the presence, rather than the extent, of malignant disease.