Objective: This study was conducted to evaluate the repair bond strength of dual-cured resin composite core materials compared to a light-cured resin composite one week or three months aging periods. Materials and Methods: Thirty-six resin composite disks were prepared. The specimens were divided according to the core resin composite material into three main groups (n=12/group), Then, each group will be subdivided into two subgroups according to the pre-repair aging period. After aging, disks were bur roughened, etched with phosphoric acid followed by adhesive application. Repair resin composite was applied to the treated surfaces. Additional specimens were prepared to test their cohesive strength. Thereafter, all specimens were sectioned ending up with a total of 360 sticks and subjected to microtensile bond strength. Scanning electron microscopic (SEM) for mode of failure evaluation of repaired specimens was done.Results: Statistical analysis using two-way ANOVA revealed no significant effect for aging period and a significant effect for the resin composite core materials after one week and three months aging. Mixed adhesive mode of failure was the most common type of failure among the tested groups. Conclusion: Dual-cured resin composite core materials can be repaired using light-cured resin composite even after three months of aging. Dual-cured resin composite core materials proved to be cogent restoration in terms of cohesive strength and reparability compared to light cured resin composite.