In this study, the relation between masticatory efficiency and masticatory stability was investigated. Thirty normal subjects were asked to chew gumi-jelly for 20 seconds. The masticatory efficiency was considered to be the amount of glucose discharge. The masticatory stability was considered to be the indicators for the masticatory path and masticatory rhythm of the mandibular incisal point. The relation between efficiency and stability was analyzed quantitatively in two analytical sections, one as the entire 20 second cycle (section A) and the other as the ten cycles beginning at the fifth cycle of mastication (section B). For example, in both section A and section B of the analysis, as the amount of glucose discharge increased, which meant the masticatory efficiency increased, the indicators for the masticatory path and rhythm decreased, which meant that the masticatory stability increased.Thus it was clear that there was an intimate correlation between masticatory stability and masticatory efficiency and that the correlation was more remarkable in analytical section B than section A. Further it was concluded that the masticatory stability and the masticatory efficiency could be quantitatively estimated by analyzing glucose discharge from gumi-jelly during chewing and by analyzing masticatory stability respectively.