Mixed silanes, 3-mercaptopropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane, were used as a primer for adhesion of poly(methyl methacrylate) to stainless steel and glass plate. The tensile bond strength of the resin to those substrates was measured after immersion in water at 37 degrees C for 3 days. The mean bond strengths of the resin to the stainless steel and to the glass plate were 23 and 17 MPa, respectively. In addition, cohesional fracture of the resin occurred in both cases. The mixture of the silanes was highly adhesive for the stainless steel and the glass plate surface treatment.