Background: In Endodontics, it is important to prevent bacterial penetration. Coronal penetration of bacteria can occur if there were inadequate temporary restorations which result in reinfection of the root canal system. Hence, the present study was conducted to compare coronal bacterial penetration in Class II endodontic access cavities with various temporary restorative materials. Material & methods: A total of 30 freshly extracted human molars were collected, stored, and surfaced. The standard class II mesioocclusal cavities were prepared. The teeth were stratified into three groups i.e. group A restored with Cavit-G, group 2 restored with IRM, and group 3 restored with Clip Flow. The data was collected and analysed using Statistical Package for Social Sciences (SPSS version 25, Armonk, NY: USA). Results: In cavities restored with Cavit-G, score 1 was seen in 7(23.33%) specimens, score 2 was seen in 3(10%) specimens and score 3 was seen 0% specimens. In cavities restored with IRM, score 1 and 2 was seen in 1(3.33%) specimens respectively, score 3 was seen in 8(26.66%) specimens. In cavities restored with Clip Flow, score 1 was seen in 6(20%) specimens, score 2 and 3 was seen in 2(6.66%) specimens respectively. Conclusion: The study concluded that although all three materials help in providing a barrier against bacteria, there was less bacterial penetration with Cavit G followed by Clip Flow and IRM. Keywords: Bacterial penetration, Cavit G, Clip Flow, IRM.