Sensitivities to recombinant human tumor necrosis factor-alpha (TNF-alpha) and chemotherapeutic agents (cisplatin, peplomycin, methotrexate) were evaluated in 20 tumor cells of head and neck squamous cell carcinomas, using a dye uptake method. Also, numbers of TNF receptors of these tumor cells were measured by Scatchard plot analysis. There was no relationship between the number of TNF-alpha receptors and the sensitivity to TNF-alpha. Furthermore, there was no correlation between the sensitivity to TNF-alpha and that to chemotherapeutic drugs, nor between the sensitivity to TNF-alpha and the clinical response to chemotherapy including of cisplatin and peplomycin. The sensitivity to TNF-alpha was higher in poorly differentiated carcinomas than in well differentiated ones.