Objectives: This study was taken to investigate factors related to dental caries in deciduous teeth of preschool children. Methods : this study was completed by oral examination on 623 kindergarten pupils and questionnaire on their mothers in Sangju city from April 1 to May 20, 2001. Study design is Cross-sectional Study. Results: The mean values for decayed teeth indexed(dt index), filled teeth index(ft index), and decayed and filled teeth index(dft index) was 2.46, 1.85, and 4.30 respectively. 2.05 for girl was significantly lower than 2.77 of boy in gender (p<0.01). As child ren got older, values were higher(0.7 and 2.84 of three years old, 1.6 and 4.01 of four, 2.42 and 5.02 of five) in ft and dft index(p<0.001). Also, Mother age was almost same, that is, 4.12 dft value for 30~34 years was smaller than 6.17 for above forties(p<0.001). 2.07 and 4.68 for mothers who graduated from high school were higher than 1.36 and 3.34 for university in the ft and dft index(p<0.05), that is, the more they had a high educational level, the lower they got a values. Value 2.76 for children who had non cariogenic food was lower than 5.11 for those who had cariogenic food in dft index(p<0.001). In dft index, 3.82 of children who have learned the education on oral health from mother frequently have lower than 45 of children who have never learned (p<0.05). The ft value of children who had a snack food with mother(1.29) was a smaller than children had it at out of home(1.97)(p<0.05). The variables related 10 dft index were children and mothers age, educational level, and kinds of snack food (p<0.05). Conclusion : This study reveals that younger girl, younger mother, higher educational level, and non cariogenic foods showed lower dft index.