The purpose of this study was to investigate the relationship between occlusal pattern factors and masticatory efficiency. 50 subjects with normal dentition were tested to obtain the occlusal pattern standard. The simplified particle counting method, which was previously reported by Imaoka et al., was used to determine the masticatory efficiency. Measurements included 5 factors of the occlusal pattern of the habitual chewing side, including the canine of each subject: the number of occlusal contact areas, the size of each area, the number of occlusal facets of the projected area, the size of the factors of the projected area and the inclination of the occlusal facets. The correlation between the 5 factors of the occlusal pattern and the masticatory efficiency were analyzed to obtain a standard for the restoration of occlusal patterns. The results were as follows: 1. The number of occlusal contacts and the number and inclination of occlusal facet were the main factors which to influenced the masticatory efficiency. 2. The standard number of occlusal contacts and occlusal facets were 15 and 25 respectively. 3. Although the inclination of the occlusal facets of premolars was slightly bigger than those of molars, the standard inclination of the occlusal facets was 25-30 degrees. 4. There was no significant correlation between the masticatory efficiency and the projected area of the occlusal contacts and facets. 5. The classification of occlusal facets should be considered, because of the inclination of the occlusal facets which appear at the same areas of the cusp point, the fossa and the marginal ridge was 10-15 degrees, and the inclination of the other areas of occlusal pattern was bigger.