Objective: The aim of the present study was to evaluate three mouth rinse solutions' (Plax, Listerine and Periogard) influence on the microhardness and color stability of a composite resin (Esthet.X, Dentsply). Materials and Methods: For this purpose, forty specimens were prepared, being 10 specimens for each solution and 10 for artificial saliva (control group). Initially, specimens were polished and immersed in artificial saliva and following the initial color, an evaluation was made. For 30 days, specimens were immersed in the solutions three times a day for 1 min. After this cycling period, color change was analyzed and Knoop microhardness measures were carried out. A new color measurement was performed after repolishing the specimens. Results: The microhardness and color stability results showed no statistically significant difference among the studied solutions. However, samples immersed in Periogard showed a significant alteration in the composite resin brightness test. Conclusion: It can be concluded that mouth rinse can influence the luminosity of composite resin.