Aside from the considerable number of reports on the physical and chemical properties of dental bonding agents, information concerning their biologic effects is sparse. Three dentin bonding agents (Prisma Universal Bond, Pertac Universal Bond, and Syntac) and the ingredients methylmethacrylate, 2-hydroxyethyl-methacrylate, and glutaraldehyde were investigated in the Salmonella typhimurium mutagenicity test system using five different bacterial strains (TA97a, TA98, TA100, TA102, and TA104). The materials as well as the ingredients were eluted in both dimethyl sulfoxide and physiologic saline, and serially diluted eluates were used in the plate incorporation test. Pertac Universal Bond and Prisma Universal Bond did not elicit any mutagenic effects in any of the bacterial strains. In contrast, Syntac adhesive showed clear mutagenicity in S. typkimurium strain TA102. Dimethyl sulfoxide eluates, as well as physiologic saline eluates of the Syntac bonding agent, caused numbers of revertants that were about 6 times higher than control values. Reversion rates with other strains were moderately enhanced. Glutaraldehyde, an ingredient of Syntac adhesives, caused mutagenicity in a manner similar to Syntac adhesive eluates. Neither 2-hydroxyethyl-methacrylate nor methylmethacrylate monomer was found to be mutagenic over a broad concentration range.