Career development gains new meaning in the context of employability demands in a knowledge economy. In this context, increased mobility, a dynamic work environment, and an increased level of career support from employers are seen as characteristics of a modern career. All of these characteristics put emphasis on individual and self-management in career development. This article presents the results of an empirical study that addressed the general question as to which competencies employees need to possess to realize career self-management. In a survey of 1,579 employees (51% response) in 16 Dutch companies, 6 career factors and competencies of career self-management prove to be relevant for career development: career development ability, reflection on capacities, reflection on motives, work exploration, career control, and networking. Among the explanatory variables that are considered, mobility perspective and career support at work and private life appear to be associated most strongly (statistical significance at 0.01) with career competencies. (Contains 3 tables and 1 note.)