To study the effect of disinfectants on dimensional stability of addition and condensation silicone impressions. Materials & methods: A total of 60 samples were enrolled. The 30 samples were of addition silicone and 30 of condensation silicone. The data was collected. A statistical analysis via a three-way mixed ANOVA was performed. The results were analysed using SPSS software. Results: There was a statistically significant simple two-way interaction of material and groups at the T1 level (p = .02), but not at the T0 level (p = .8). That interaction arises from the statistically significant differences between the control groups of the two materials (p=0.05). Conclusion: The dimensional changes of all the samples were significant.