Background: 60–90% of schoolchildren are exposed to dental caries in both developing and developed countries. Furthermore, among Middle-Eastern schoolchildren studies have shown that the prevalence of dental caries was up to 83.3% .and in Egyptian children and adolescents (3-18y) were examined over one year, 74% of them had dental caries. Glass ionomer can form general chemical bonds with tooth substrate and display adequate margin sealing. Aim: This study aimed to evaluate and compare The Micro hardness of Glass ionomer(FUJI I), Highly viscous glass ionomer (EQUIA)and Bioactive material restoration(ACTIVE) in class V cavity in primary molars. Matrials and methods: A Thirty six extracted primary upper second molars with prepared class V cavity fulfilling the inclusion criteria for microhardness test was divided in three groups according to types of restorative materials ( FUJI I(I), EQUIA(II) and ACTIVA(III) )So, n=12. Results: the statically analysis showed that the highest micro hardness were recorded in EQUIA (mean HV= 51.4 kg/mm2 ) followed by ACTIVA (mean HV= 51.4 kg/mm2 ) and the lowest microhardness were recorded in FUJI I (mean HV= 50.3 kg/mm2 ). Conclusion: EQUIA (the high-viscous glassionomer restoration) has highest microhardness than other two restorations