Aim: To find a suitable disinfectant additive with effective antimicrobial activity and physical properties to dental gypsum product. Methods and materials: Design and settings of the study involved three compounds; Silver nitrate (0.3%, 0.5%, 1%); Copper Sulfate (0.5% and 1%), and Potassium Permanganate (0.5% and 1%). Antimicrobial properties, setting time, compressive strength (1 hour and 24 hours) and reproduction of surface details were evaluated. Standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans were used in the study. Dental stone was mixed with test compounds and plain water (control) were sampled in punch well on agar plates which were incubated at 37°C for 24 hours. Mean of Minimum Inhibitory Zone (MIZ) in mm, was measured at 24 hours. The setting time was measured by standard indentation, Compressive strength using Universal testing machine and reproduction of surface details as per ADA guidelines. Statistical analysis of the data was done using one-way ANOVA with Tukey's post hoc test using Graph pad Prism Version 5. p-value of < 0.05 was considered as statistically significant. Results: Silver nitrate showed excellent antimicrobial activity against all the microorganisms. The setting time with 0.5% Silver nitrate was between 30 and 34 minutes, the compressive strength was found to be greater than the control and the surface details were acceptable. Thus, 0.5% silver nitrate was reported as an alternative disinfectant for gypsum products. Conclusion: An amount of 0.5% silver nitrate could be safely suggested as suitable disinfectant additive for gypsum product. Clinical significance: The antimicrobial property imparted to the stone reduces the risk of cross-infection among dental personnel, patients and lab personnel from bacterial, viral, and fungal microorganisms that remain even viable after cleansing and disinfecting the impressions.