This study evaluated the effect of atmospheric pressure plasma (PL), sandblasting with aluminum oxide (SA), and the on the bond strength of fresh bulk-fill resin composite to water-aged restorative bulk-fill resin composite. Seventy pre-polymerized composite plates were fabricated using Filtek Bulk Fill Posterior Restorative (3M ESPE) stored in distilled water for 4 months and randomly divided into 4 groups. For all specimen, two resin cylinders were made using a 1,4 mm diameter x 1 mm height matrix. The resin cylinders were tested after 24 hours, using shear test device. Data were analyzed by 2-way ANOVA and Tukey’s test (5%).