Determination of 15 elements in the dental porcelain powders (Vita VMK 68) marketed in Japan was done by means of non-destructive neutron activation analysis. The potassium and sodium contents showed less variations from powder to powder, and the uranium contents varied from a few ppm to 1090 ppm in a wide range. The high contents of uranium (345--1090 ppm) were detected in the powders of Enamel, Dentin, Effect, Color and Gum which were used for the superficial parts of a porcelain crown, while the low contents of uranium (1.6--2.7 ppm) were detected in those of Opaque and Translucent which were used for the core part and the top of the crown. Cerium and samarium were also detected in each powder in the amounts similar to those of uranium. The main radionuclides present in the porcelain powders were 238U, 235U, 234U, 234mPa, 234Th, 231Th and 40K. The activities of these nuclides were calculated and discussed.