Introduction: For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. Materials and methods:A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with selfdisinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness.Results: Difference in surface hardness was statistically insignificant (p > 0.05). Conclusion:Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable.Clinical significance: Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material.