Aim: The purpose of this study was to clinically evaluate conventional glass ionomer versus nano filled glass ionomer as a restorative material in proximal cavities of primary teeth. Methods: This study included 60 primary molars in 60 children 4–9 years of age who underwent an identical conventional class II cavity preparation the study sample was divided equally into two groups according to the type of filling material group A filled with nano filled glass ionomer , group B filled with conventional glass ionomer The patients were recalled after an interval of 3 months and 6 months for evaluation of restorations using USPHS Cvar/Ryge Criteria. Results: Nanoionomer was significantly better than conventional glass ionomer with respect to color match at 3 months, 6 months (P<0.001). Nanoionomers were also significantly better than conventional glass ionomer in case of cavosurface marginal discoloration and marginal adaptation (P<0.001) at 6 months. There was no significant difference between the two materials with respect to secondary caries at 6 months (P>0.05). There was no statistical significant difference with respect to anatomical form and postoperative sensitivity (P>0.05). Conclusions: Nanoparticulated resin-modified GIC, which is the latest development in a long history of GIC with improved properties, can be a reliable alternative to the other glass ionomer restorations.