introduction: Erosion is a common condition that is related to consumption of acidic food and drinks such as; carbonated drinks and fruit juices that might cause early deterioration of the dental restorations. Abrasion of dental restorations might result from physical factors such as tooth brushing or polishing.   objective:  This study aimed to assess the combined erosive potential of  cola soft drink and orange juice, and the abrasive potential of air-polishing, on the surface of nano-filled composite resin restorations via evaluation of microhardness and surface roughness.   materials and methods: A total of 60 specimens were prepared from nano-filled composite resin. Specimens were divided into 3 groups according to the immersion media (water, cola, orange juice), and each was further subdivided into 2 subgroups (unpolished or polished). Surface hard- ness was measured using a digital micro-hardness tester, and surface roughness was recorded using a profilometer. Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's post hoc test.   results: A significant decrease in surface hardness was observed on immersion of nano-filled composite in either cola or orange juice. Except for the control group, the air-polished specimens had significantly higher surface hardness when compared to the unpolished ones. Cola and orange juice had a significant roughening effect on composite resin surface. Further increase in Ra values was recorded after air-polishing of both groups.   Conclusion: Combining beverages immersion with air-polishing may have a profound effect on the surface deterioration of nano-filled composite resin