INTRODUCTION: Nanotechnology was used in the development of glass ionomer cements to provide some value added features not typically associated with this type of restorative materials. OBJECTIVES: This study was conducted to evaluate the surface roughness and solubility of a nano filled resin modified glass ionomer cement and to compare it with a conventional type of glass-ionomer cement. MATERIALS AND METHODS: Forty disc shaped specimens were prepared using Teflon split mold according to manufacturer instructions. Specimens were divided into two group :Group A (20 specimens prepared from Ketac Nano) and Group B (20 specimens prepared from Ketac Molar). Each group was subdivided into two subgroups of 10 specimens each. Twenty specimens from different subgroups were subjected to surface roughness test. The other twenty specimens from different subgroups were subjected to solubility test. Data were collected, tabulated and statistically analyzed. RESULTS: Concerning surface roughness; Ketac Nano showed statistically significantly lower surface roughness than Ketac Molar where the mean values were 0.27 ± 0.10 μm and 0.48 ± 0.14μm respectively. Concerning solubilty; Ketac Nano showed statistically significant lower solubility than Ketac molar where the mean values were 4.25 ± 1.87 and 12.16 ± 2.89 μg/mm3 respectively. CONCLUSIONS: It was concluded that the addition of nano-fillers to RMGI seemed to decrease its surface roughness and to improve but without completely eliminating the solubility of the nano-glass ionomers