This paper examines adequate, university based professional preparation of employees in the field of adult education, intertwined with continuing professional learning, based on increasing professional and academic knowledge in the field of andragogy as the key condition for the transformation of occupation to the profession of adult educator. Researching of the process of the professionalization of adult educators was based on complex instrument for gathering data (questionnaires, five-point Likert-type scales, and of Mokken type scales). The collected data from the sample of more than 680 adult educators in Serbia were subjected to few common (frequencies, Kolmogorov-Smirnov Z test, etc.), and more complex proceedings (canonical correlation analysis and Maximum Likelihood Factor Analysis). Research findings suggest importance of previous professional preparation and continuing professional learning which represents the key factors in the process of professionalization and influence expression of elements of the profession: autonomy, social control, personal social status, ethics, standards, associations, and subculture. Findings also suggest that professional knowledge influence performance, responsibility, commitment, and selection of professional roles and dominant tasks and duties of employees in the field of adult education.