Aim: This study was carried out to examine the influence of two different surface coating materials ( PermaSeal and G-coat Plus) on marginal leakage of nanofilled resin composite and glass ionomer restorations.Materials and methods: Class V cavities were prepared on the buccal or lingual surface of sixty sound human non-carious teeth (first and/or second premolars). They were divided into 2 main groups, 30 teeth each, according to the restorative material to be used for restoration of the cavities (R); where R1 denotes Filtek Z350 XT resin composite and R2 denotes Fuji IX gp extra. Each group was further subdivided into 3 subgroups, 10 teeth each, according to the low viscosity surface sealant material used (S); where in S0 no surface sealant was used (control untreated group) while in S1 PermaSeal was used and in S2 G-coat Plus was used. After 2 week storage in artificial saliva, microleakage at the cavity margins was assessed by dye penetration using 2 % methylene blue solution and image analysis was done by computerized program to calculate the linear dye penetration in (mm). Then data were recorded, tabulated and statistically analyzed.Results: According to data obtained, comparing the effect of surface coat materials regardless to type of filling materials, it was found that G-coat Plus group recorded the least amount of marginal leakage followed by PermaSeal coat group while control group recorded the highest amount of marginal leakage. Conclusion: The application of a surface sealant is effective in the reduction of microleakage at the margins of esthetic restorations. Also microleakage at prepared cavity margins could not be totally eliminated by any of tested materials; it could be reduced but not terminated.