The diploma thesis deals with legal aspects of electronic commerce in several phases beginning with electronic contraction, then fulfillment of contracts, electronic payments and consumers’ protection. Attention is paid to the specifics of electronic contracting like special contract types, international legal aspects of using the Internet, electronic signature, electronic auctions and its practical realization. Where the legal regulation is not very precise, there is given a concept of solution. The diploma thesis involves foreign experiences from the European Union, USA and Australia.