The adherence of Candida species to saliva-coated plates of polymethyl methacrylate resin was studied physico-chemically. Saliva-coating of the resin plate caused increasing adherence of C. albicans, whereas it caused decreasing adherence of C. tropicalis. The hydrophobicities of the surfaces of the resin plate and the candidal cells were evaluated by a contact angle method, and surface free energies of these surfaces were calculated. The candidal cell adherence to the saliva-coated plates was highly correlated with the free energy change in hydrophobic interaction.