Background: The development of caries is dependent on the interaction of four primary factors. These are a host (tooth surface), a substrate (food), the presence of oral bacteria, and time. Caries will not develop if any of these four primary factors are not present. Although the primary molars are naturally replaced by the age of 10–12 years, caries, pulpitis, periapical periodontitis, primary molar defects, even loss of primary molars can have adverse effects on the permanent teeth. The bite force is created by the dynamic action of the muscles during the physiologic act of mastication. Determination of individual bite force level has been widely used in dentistry, mainly to understand the mechanics of mastication for evaluation of the therapeutic effects of prosthetic devices and to provide reference values for studies on the biomechanics of prosthetic devices. Methods: The 4-5 year olds who were treated at the National University of Medical Sciences, School of Dentistry, Dental Hospital were admitted to this study. The magnitude of the bite force in Newtons (N) was measured (Occlusal Force Meter GM10) bilaterally corresponding with the 1st and 2nd primary molars using a specifically designed single tooth bite force gauge. Results: Fifty three children were included in the study. The prevalence of dental caries was found to be 66.04% respective. No significant differences were found between the male and the female in bite force and p values of the study. Analysis of variance evaluated difference among the three groups. The means of maximum bite force were 258.83, 216.43 and 189.15 N for the groups. Significant differences between first molar and second molar’s occlusal surface area were detected. The analysis of correlation showed that the caries and bite force presented weak inverse (r=-0.36) correlation. Conclusion The bite force of 4-5 years old children was independent of gender, body weight, body height and side of mastication. The bite force on teeth with caries were 189.15 N. The caries was in weak inverse correlation with the bite force quantity. The amount of bite force measured was dependent on tooth occlusal surface area.