This thesis explores selected legal problems that arise in the formation of online contracts in the American and English legal systems. The thesis examines to what extent traditional contract law rules provide a satisfactory legal ground for governing such issues. It attempts to show that no substantial legislative reform is necessary as adaptations of traditional contract law rules are sufficient. To this end, this study focuses on questions regarding the formation of email contracts, the role of electronic agent in forming website contracts, the distinction between offer and website advertisement, online errors and mistakes, web site acceptance, and finally, the incorporation of online terms.