The author measured vertical dimension of 675(326 of male and 349 of female) in normal Korean adult from 20 to 50 years of age between upper and lower muco-buccal fold on upper and lower central incisal portion at centric occlusion state. The following results were obtained.; 1) The distances from upper muco-buccal fold on upper anterior central incisal portion to lower muco-buccal fold on lower anterior central incisal portion at centric occlusion state were 37.57mm in male, 36.80mm in female and 37.19mm in average. The distances in male were longer than those of female. 2) According to increase age(from 20 to 50 years of age), the tendencies of vertical dimensional changes were increased slightly in 30~40 years group and decreased after 40 year in both sex. 3) The distances from upper muco-buccal fold on upper anterior central portion to upper central incisal edge were 20.77mm and from lower muco-buccal fold on lower anterior central incisal portion to lower central incisal edge were 18.88mm. The ratio between maxillary distances and mandibular distances was 1.4:0.9.