Aim: To evaluate and compare the linear dimensional stability of two commercially available BD IMPRESS and NEXUS MEDODENT thermoplastic impression materials. A total of 90 samples in which 45 s Methodology: amples of BD Impress and Nexus medodent impession materials were used for evaluation of linear dimensional stability of these newly introduced thermoplastic impression materials. The samples were rst checked under toolmaker microscope for reproduction of three parallel lines x,y,z. The measurements were made on the samples at 0 (within 24 hours), 7th and 14th day respectively to assess the linear dimensional stability. According to the study conducted and results obtained, it Result: was concluded that NEXUS MEDODENT was superior in linear dimensional stability on comparison with BD IMPRESS impression material Conclusion: On comparison with BD impress, nexus medodent impression material was superior in terms of linear dimensional stability. There is a need for further studies to know about other properties of these thermoplastic impression materials to enhance knowledge and for clinical application as indicated by manufacturers.