Aim: The aim of the study is to assess the color stability of nanofilled and microhybrid dental composite resins when exposed to chlorhexidine mouthwash.Materials and Methods:Thirty specimens (15 specimens for each group) were crafted using a composite filling instrument. Each specimen measured 12 mm × 4 mm and was of A1 shade. All prepared samples were individually submerged in 30 ml of distilled water in separate containers based on their respective groups. Following a 24-hour immersion period, baseline color values of each sample were measured using a spectrophotometer.Following initial color measurements, 15 randomly chosen specimens per group were immersed in 30 ml of clohex ADS mouthwash for 24 hours. Data analysis was performed using SPSS.Results: Both samples exhibited color changes after immersion in the mouthwash, yet these changes were not statistically significant.Conclusion: The study's conclusion highlights that nanofilled composite resins demonstrate higher colorimetric stability than microhybrid composites when subjected to chlorhexidine mouthwash exposure.