At the brink of the new millennium, in global economy and commerce, there has been a dramatic increase in the role of information technology in markets, both in traditional markets and especially in the emergence of the electronic marketplaces. In recent years, the Internet has grown exponentially and is clearly transforming global markets. This chapter analyzes the fundamentals of electronic commerce and discusses the opportunities and challenges that e-commerce presents for global enterprises with relevant examples from the industry where appropriate. Opportunities of e-commerce are improvements in marketing activities such as one-to-one marketing and communication, better management of product/service support and product/value chain, and cost cuttings due to several electronic payment methods. On the other hand, global enterprises face the challenges of e-commerce, such as adjusting to competition in electronic markets, re-engineering/e-engineering distribution channels, addressing security and privacy issues, and applying strategic management to corporate alliance systems. Finally, the future of electronic commerce is discussed.