Human assets are one of the most important resources available to any organization and employee competence and commitment largely determine the objectives that an organization can set for itself and to its success in achieving them. Therefore, the demand for effective employees continuously increases in both public and private organizations. The 'Competency-based' approach to human resource management has become integral during the last thirty years, with 'Competency' encompassing the knowledge, skills, abilities, traits and behaviors that allow an individual to perform a task within a specific function or job (Boyatzis, 1982).The objective of this study is to identify the required competencies and develop a competency model for effective job performance at the Chief of the General Administrative Sub-Division position level in the Thai Department of Agriculture using the Behavioral Event Interview (BEI) technique (Spencer & Spencer, 1993). The study found that there were twenty-three competencies that superior job performers used in carrying out this job well. Consequently, the researcher uses current level of importance of competency as primary information to recommend nine competencies in a competency model.This competency model will help the Thai Department of Agriculture to respond to government policy regarding human resource management, provide useful information Contemporary Management Research 46 about the specific characteristics required at the Chief of the General Administrative SubDivision level and on how to implement further enhancement of employee performance at this level. These competencies will also enable the Department to determine the critical competencies necessary for current success at this job level and the strategic competencies necessary for future success.