There was a great need to consider a core competency-based approach as a new direction of the science education for gifted students according to the value and vision of the 21st century knowledge-based societies. Therefore we developed a core competency model of scientist and examined its validity as a prerequisite for a core competency-based education of science gifted students. In order to this, the survey was conducted after developing questionnaire through the theoretical review of the various resources such as paper, book, and newspaper articles and the qualitative analysis of the behavioral event interview, and then an exploratory factor analysis was performed to validate the factor structure based on the results of the survey. The results revealed that the core competency model with the 5 cluster units of competency and the 15 core competencies was potentially constituted. And the reliability, convergent validity, and discriminant validity of the core competency model were verified through the confirmatory factor analysis. The cognitive cluster consisted of 5 competencies and they were as follows: creative, comprehensive, exploratory, analytical, and conceptual thinking competency. The achievement-orientation cluster consisted of 3 competencies and they were as follows: initiative, preparation & problem solving, and strategic influence competency. The scientific attitude cluster consisted of 3 competencies and they were as follows: flexible thinking & attitude, passion for research, and views about science competency. The personal effectiveness cluster consisted of 2 competencies and they were as follows: diverse experiences and global attitude competency. Finally, the networking cluster consisted of 2 competencies and they were as follows: personal understanding and communication competency. Findings were expected to provide the basic data for developing programs and establishing strategies based on the core competency as well as introducing the core competency model of scientist to science education for gifted students effectively.