The relevance of E-Learning grows especially in continuing and further education as well as in informal learning. This contribution considers how we can do gender mainstreaming of E-Learning designs. Starting with a short review of gender differences in education, learning related abilites and activities, computer related activities and attitudes, and theories to understand these differences, the main gender mainstreaming approaches in education are presented and a general design guideline for gender inclusive didactics of E-Learning is developed. An implementation is described and empirical findings are discussed in the context of gender differences in computer usage and interest, ease of use, usage, motivation and interest, as well as in learning outcomes (n=143).