Objectives : The purpose of this study was to examine the satisfaction level of dental hygienists with supplementary education. The subjects in this study were 305 dental hygienists, on whom a survey was conducted from September 26 to December 10, 2009. Methods : The instrument used in this study was questionnaires that consisted of three sections: educational environments, the content and method of education, and educational administration. Results : The findings of the study were as follows: 1. In terms of satisfaction level with supplementary education, they gave a mean of 3.13, which was on the average. The dental hygienists who worked in public dental clinics, who had a 10 years or more of career and who worked in the provinces expressed more satisfaction. 2. In terms of satisfaction level with educational environments, they gave a mean of 3.22. They were most gratified with lecturers(3.34), and they expressed the least satisfaction with educational opportunities(3.14). 3. In terms of satisfaction level with the content and method of education, they gave a mean of 3.15. They were most contented with the professionalism of education, and they expressed the least satisfaction with the ratio of theory and practice(2.92). 4. In terms of satisfaction level with educational administration, they gave a mean of 3.02. They were most satisfied with the application procedure(3.22), and they expressed the least satisfaction with educational cost and publicity(2.91). Conclusions : Educational institutions that provide supplementary education should reinforce small-group supplementary education for each district, provide systematic practice-centered educational programs and offer streamlined administration service to boost the satisfaction level of dental hygienists.