The purpose of this study was to investigate the width of attached gingiva of young adults with healthy gingiva. We compared the differences according to the tooth location. The width of attached gingiva of maxilla and mandible was measured by histochemical method. The results were as follows: 1. The width of buccal keratinized gingiva in maxilla was widest in incisors(5.2-5.6mm) and narrowest in first bicuspids(4.4-4.5mm). 2. The width of buccal keratinized gingiva in mandible was widest in incisors(4.3-4.5mm) and narrowest in first bicuspids(3.2-3.3mm). 3. The width of lingual keratinized gingiva in mandible was widest in first molars(5.5-5.6mm) and narrowest in incisors(2.9-3.0mm). 4. The width of buccal attached gingiva in maxilla was widest in incisors(4.1-4.4mm) and narrowest in molars (3.0mm). 5. The width of buccal attached gingiva in mandible was widest in incisors(3.2-3.4mm) and narrowest in second molars (1.7-1.8mm). 6. The width of lingual attached gingiva in mandible was widest in first molars(3.5-3.7mm) and narrowest in incisors(1.9-2.1mm).