Professional qualifications for adult educators have been a subject for discussion and research for more than thirty years. The content and form of adult educator training programmes have been debated vigorously. In this article we illustrate the advantages of competence development as in-service training. Thus, our focus is on describing how competence development of adult educators can be accomplished as an integral part of daily practice in (adult education) colleges. In the Danish example presented, we show how in-service training can have a great impact on the teachers’ self-understanding, the educational culture of the college, and even on dropout rates. To better understand the conditions for this kind of training, we start with a brief overview of the qualifications needed to teach in different adult education sectors in Denmark.