Objectives: Resilient denture-lining materials are more susceptible to microbial adhesion than are denture base acrylic resin. As denture hygiene is essential to maintain the serviceability of the denture, disinfectant solutions have been suggested as a method for effectively cleaning resilient liners. The aim of this study was to determine the effectiveness of four different disinfectant solutions on four different resilient lining materials contaminated with Staphylococcus aureus, Streptococcus sobrinus, and Candida albicans. Method and materials: Three microorganisms (Sta aureus, Str sobrinus, and C albicans), four resilient lining materials (Tempo, Immediate, Flexacryl soft, Ufi Gel P), and four disinfectant solutions (5.25% sodium hypochlorite, 2% sodium hypochlorite, 5% Deconex, and 3.5% Savlex solutions) were investigated. The four resilient lining materials were contaminated with each of the microorganisms, then the disinfection tests were applied to detect the efficacy of disinfectant solutions on resilient denture base materials in an in vitro test. The specimens (n = 5, total = 240) were soaked for 5 minutes in each solution to disinfect the microorganisms. The control specimens (one of each material; n = 5, total = 60) were soaked in distilled water for 5 minutes. As a result, a reduction in microorganism counts was determined. The Kruskal-Wallis and one-way analysis of variance tests were used to analyze for significant differences among test groups at the level of significance. Results: For all microorganisms, soaking in 5.25% sodium hypochlorite reduced the number of viable adherent microorganisms significantly compared to soaking in 2% sodium hypochlorite, which led to greater reduction than soaking either 5% Deconex or 3.5% Savlex. The use of 5.25% sodium hypochlorite in all groups is statistically significant. Conclusion: Disinfection of four different resilient denture-lining materials with 5.25% sodium hypochlorite solution was the most effective immersion technique. To achieve an efficient disinfection, the immersion time of the other disinfectant solutions could be increased. Keywords: disinfection, microbiology, microorganism, resilient soft-lining materials