Objective: The purpose of this study was to evaluate the effects of some commonly used disinfectants on physical properties of four temporary soft denture-liner materials. Method and materials: Soft-liner materials, including three plasticized acrylic resin-liners (Tempo, Immediate, Flexacryl Soft) and one silicone-based material (Ufi Gel P) were studied. Specimens prepared with the soft-liner materials were tested after the application of disinfectants (5% Deconex and 3.5% Savlex for 10 minutes; 2% sodium hypochlorite and 5.25% sodium hypochlorite for 5 minutes) and were compared with the control group (not disinfected; immersed in distilled water). Five specimens of each material were tested and data collected on days 4, 7, 11, and 15. The hardness values were determined using the Shore A hardness test. Results: Water sorption test results showed that the disinfectants had statistically significant effects on water sorption values (except days 7 and 15 for Flexacryl Soft and days 4, 7, and 11 for Ufi Gel P). Water solubility and hardness test results also showed statistically significant effects on the materials by the disinfectants. Conclusion: Disinfectants significantly affected the physical properties of water sorption, water solubility, and hardness of the soft-liner materials.