Commercially available bonding-agents and composite resins were employed in this study to investigate the cytotoxicity of dentin-bonding composite resin, using human gingival fibroblasts in cell cultures. The cells were seeded on the resin surfaces cured with various periods of light illumination. The cells were cultivated for 1,3 and 6 days, and cell morphology was observed using a phase contrast microscope and a light microscope. The number of living cells on the uniform area of the resin surfaces was counted for 1,3 and 6 days of cultivation for quantitative evaluation of cytotoxicity. After 24 hours of obsevation, the cells were attached to the surfaces of the bonding-agents and composite resins. The cell attachment rate was however suppressed in comparison with the growth of the control cells. The greater cell growth of LB and AP-X was demonstrated with the longer light illumination. On the other hand, the cell growth of MP and Z 100 was not affected by the number of the seconds of light illumination. The number of cells did not increase as much as the control cell growth in 1,3 and 6 days of culture. However, the lesser cytotoxicity of the cured bonding agents and cornposite resins was suggested by the result of the adhesion and growth of cells on the resin surface.