Aim: To assess the effect of combining 0.2% chlorhexidine (CHX) mouthwash with xylitol (XYL) chewing gum on Streptococcus mutans and biofilm levels among 8- to 12-year-old children. Materials and methods: Sixty children aged 8 to 12 years were selected with moderate and high salivary S. mutans levels. They were divided into three groups of 20 children each: (1) XYL group where the subjects chewed XYL twice daily; (2) CHX where rinsing was done twice daily; and (3) combination of XYL and CHX group (XYL+CHX) where both the agents were used once daily. The S. mutans colony-forming units (CFUs) were counted by using the mitis salivarius agar plate at the beginning of the study and at 15 days, 1, 2, and 6 months from the start of the study. Results: The XYL+CHX group showed the maximum reduction in both the biofilm and S. mutans scores throughout the study period. Conclusion: The XYL+CHX combination reduced both the biofilm and S. mutans score significantly better than either XYL chewing gums or CHX mouthwash used alone. How to cite this article: Syed M, Chopra R, Shrivastava V, Sachdev V. Comparative evaluation of 0.2% Chlorhexidine Mouthwash, Xylitol Chewing Gum, and Combination of 0.2% Chlorhexidine Mouthwash and Xylitol Chewing Gum on Salivary Streptococcus mutans and Biofilm Levels in 8- to 12-Year-Old Children. Int J Clin Pediatr Dent 2016;9(4):313-319.