The explosive growth of Internet-based electronic commerce has increased the consumer’s choices of goods and merchants. To find a suitable good and merchant with acceptable sales terms is a very tedious task. Agent technologies promise to simplify these tasks for consumers. This chapter presents an overview of electronic commerce systems based on software agent technology. A survey of current existing and prototype systems are presented. One of essential requirements of a successful e-commerce system is security measurement. This paper also discusses security issues related to implementing agent-based e-commerce.