Background: Dental impression making is the process of creating a negative form of the teeth and oral tissues. A variety of dental impression materials are available these days for making replica of the oral cavity. The accuracy of these impression materials shows considerable variations. Hence; we planned the study to assess the efficacy and accuracy of addition and condensation silicon impression materials in making duplicate dies. Materials & methods: The present study included assessment of efficacy of addition silicon and condensation silicon in making duplicate dies. Preparation of an acrylic model of the upper premolar tooth was done on the basis of conventional shoulder type marginal preparation supragingivally. Impression was taken followed by pouring of dental stone. Stone casts were separated from the impression and were stored for final setting. 20 successive impressions were then made, ten for each of the impression material. Fabrication of the die was done. All the results were analyzed by SPSS software. Results: On comparing the overall discrepancies, Speedex material showed significant overall discrepancy while non- significant discrepancy was observed in Panasil material. Conclusion: Panasil material has better marginal accuracy in making duplicate dies. Key words: Die, Impression, Materials