In this paper, we propose a visual language based approach to support an instruction designer in the creation of e-learning activities, distance courses and assessment tests. In particular, we have extended UML Activity Diagrams to make them suitable for the definition and generation of e-learning activities. The language is turned out to be also a powerful tool for presenting e-learning activities to end-users by providing them an easy user interface which allows us also to keep track of students' progresses. We also present a system prototype based on the proposed approach. The system includes integrated modules for several authoring activities, such as distance courses, assessment and self-assessment. © 2003 IEEE.