Background: The polymerization process occurs when monomers bind to each other to form polymers and if there is a bond between oxygen molecules and free radicals, the polymerization can be inhibited by oxygen diffusion and form an oxygen inhibited layer (OIL) on the surface of the composite resin. Glycerin applied to the surface of the composite resin before the curing process was able to reduce the formation of OIL, thereby increasing the hardness and decreasing the surface roughness. The surface roughness of the composite resin is related to changes in the microstructure such as porosity. The use of glycerin on the surface porosity of composite resins has not been fully explained, so it needs further research. Purpose: To Prove porosity of the nanohybrid composite resin filled with and without glycerin coating before curing. Methods: This research is an experimental laboratory conducted using a post-test only control group design which includes two treatment groups, namely nanohybrid composite resin without glycerin and nanohybrid composite resin treated with glycerin. This research was conducted to examine the surface porosity of the nanohybrid composite resin using a Scanning Electron Microscope (SEM). Results: There was a significant difference (p<0.05) in the porosity of the nanohybrid composite resin without glycerin and with glycerin analysis. Conclusion: There are differences in the amount of porosity in the composite resin with coating and without glycerin coating on nanohybrid composite resin fillings.