I Introduction: Currently, removable denture is still an option in replacement of missing teeth. Denture will be in the mouth for a long time. The release of the compound of denture materials such as monomer methylmethacrylate (MMA) as a result of incomplete polymerization can cause adverse effects to the body in the form of toxicity, allergic effect, and mutagenicity. Genotoxicity test with the micronucleus test is one method of testing to investigate the biocompatibility of denture base materials on the body. Objectives: To evaluate whether if there’s any different genotoxic activity in the denture base materials that is commonly used in daily practice in the field of dentistry, such as polyamide thermoplastic, heat cured thermoplastic acrylic, and self cured thermoplastic acrylic. Methods: Extract of both materials were made by incubating both sample in pH 6,8 artificial saliva in 24, 72, and 168 hours. Followed by the cytokynesis block micronucleus assay on lymphocytes. Results: There are differences in the genotoxic activity, seen by the micronucleus frequency of 1x103 binucleus cells. Denture base material type of heat cured acrylic thermoplastic and thermoplastic polyamide performed on men and women show micronucleus frequencies below 0,040 for all of the three test time. Micronucleus frequency for self cured thermoplastic acrylic types in men and women for all of the three test time showed micronucleus frequencies above 0,040. Conclusion: There are differences in the release of MMA in artificial saliva medium at all three material denture tested. This affects the genotoxic activity in the denture base materials.