Development of the civilization was always accompanied by the knowledge and technological progress. Tools made us more skilful, capable and efficient. we currently observe intensification of transformations. Complementary education is a concept which assumes that the teaching-learning process should flexibly combine traditional education and, characteristic for it, direct communication with remote education, using the Internet and other forms of media. The essence of complementary education for sustainable development is to combine these two modes of education so that the individual elements are matched to each other, complement each other and are tailored to the needs and abilities of the student and teacher. Among these media, the computer and the Internet play a key role.