This dissertation aims to understand what are consumers' privacy and security concerns and how the different techniques can be used to protect their privacy and security on the Internet. Thus online companies would gain competitive advantage over their rivals. In this dissertation we first look at the history of the Internet and WWW to have the basic idea of emergence of E-commerce. After giving a broad background to the Internet and E-commerce, we concentrate on consumer's privacy and security concerns during their purchasing goods/ services online. In chapter 2, it explained in detail what are privacy and security and the levels of concerns. Chapter 3 discusses the main risks and threats relating to consumer security and privacy in e-commerce. In chapter 4, we will look at various privacy and security measures that have been developed to protect consumers' privacy and security on the Internet. These techniques can reduce fraud, unauthorized access to consumer personal information, and network security breaches. Chapter 5 is an analysis of the survey (primary research) on what consumer perceive of privacy and security on the Internet.