To improve chewing ability and chewing behavior among preschool children, we conducted a 5-month education program with children aged 5 to 6 years and their guardians. Using a quasi-experimental design with assessments before and after intervention, the effectiveness of the program was evaluated by comparing the intervention and control groups. The program consisted of three lessons with practical exercises, chewing training six times using a chewing gum that changed color, and counting the number of chews during lunch with a chewing counter. Activities for guardians consisted of one lesson and five letters. Although the maximum bite force increased in both the intervention and control groups according to the children's natural development, masticatory performance as assessed by the color-changing gum improved significantly in the intervention group (before : 16.8±7.4, after : 20.1±6.8) but not in the control group (p<0.05). Chewing behavior as evaluated by the number of chews per minute during lunch also improved significantly (before : 28.1±10.9, after : 37.6±13.2 ; p<0.01). The results of questionnaires completed by guardians before and after intervention showed an improvement not only in the chewing behavior of children, but also in guardian awareness regarding use of ingredients and preparation of meals that assist in the development of children's chewing ability.