The aim of the present paper is to describe the process of developing an e-learning system for continuous medical education in the field of occupational medicine, with special focus on usability. The following steps are described: the needs analysis of the potential users; the prototype of the system that has been set up; the usability evaluation of the prototype by a sample of ten users; the analysis of the potential improvements; the evaluation of the revised system. The results of the usability tests point out that investing in improving usability was useful, even when they have not been recommended as mandatory. Only data collected from real active users will provide a more exhaustive evaluation, nevertheless it can be considered that positive results can be expected.