This study was intended to develop and validate the Korean version of the Adult Career Concern Inventory. 147 items and 19 factors of the inventory were obtained based on open-ended questionnaires. A preliminary on-line survey from 336 employees was carried to collect data. Exploratory factor analyses excluded two factors such as person-environment fit and hobby and resulted into 115 items and 17 factors. To test the validity of the career concern inventory, the main on-line survey was carried and the questionnares were collected from 1091 employees. In order to check cross-validity of the scale, the total group was divided into two sub-groups: Group 1, 546 employees, and Group 2, 545 employees. The results of confirmatory factor analyses of Group 1 showed that the 16-factor model fit the data better after the vision-on-the-job factor was eliminated together with some items, which finally resulted in 94 items and 16 factors. These 16 factors were as follows: 1) retirement, 2) career management, 3) work-family balance, 4) interpersonal relations, 5) turnover, 6) health, 7) job performance stress, 8) establishing a business, 9) indecisive attitude, 10) promotion, 11) economic issue, 12) service, 13) marriage issue, 14) work sustainability, 15) competence improvement, and 16) lack of professionalism. The career concern inventory was significantly correlated with various criteria such as performance, job satisfaction, organizational commitment, career satisfaction, career commitment, mental health, life satisfaction etc. Finally, implications and limitations of this study and the directions for future study were discussed.