Objectives: This in vitro study was carried out to assess the microtensile bond strength ofresin composite to dentin pretreated by antimicrobial silver nanoparticle and tested at twodifferent aging times (24 hours and 3 months). Methods: Spherical silver nanoparticles weresynthetized. 10 ml of 1% ethanolic solution of Polyvinyl Pyrrolidone and 0.2 ml SilverNitrate powder were mixed in a closed test tube containing 25ml distilled water and placedin a microwave oven that was operated at 1000W and frequency 2450MHz for 5 seconds.The colorless solution instantaneously turned to the characteristic yellow color, indicatingthe formation of silver nanoparticles. The occlusal surface of 60 human molars were groundflat to expose both the superficial and deep dentin levels in each tooth. Half of the specimenswere treated with silver nanoparticles after etching and the other half works as a control.Adper Single Bond 2 adhesive system was applied and cured followed by build-up using anano-filled resin composite (Filtek Z350XT). Each specimen was sectioned to produce 1mmdiameter sticks used for the test. Resin dentin interface were analyzed using EnvironmentalScanning Electron Microscope. Results: Both superficial and deep dentin level, non-treatedwith nanoparticles recorded statistically significant higher microtensile bond strength meanvalue than that treated ones after 24 hours aging period (p > 0.05). With the specimenstested after 3 months aging , superficial dentin level, treated with nanoparticles recordedstatistically significant higher microtensile bond strength mean value than that non- treated ,while with the deep dentin level, statistically non-significant difference in the bond strengthbetween treated and non-treated specimens appeared (p > 0.05).Conclusion: Silvernanoparticles are a promising antibacterial pretreatment agent that didn’t antagonizepenetration of resin tags into dentinal tubules. Spherical shape silver nanoparticles in ethanolbased solution did not hinder bonding of resin composite to dentin.