Cloud computing has recently emerged in prominence and is being rapidly adopted by organizations because of its potential and perceived benefits of flexibility and affordability. According to surveys conducted in 2008 and 2009 by International Data Corporation (IDC) of IT executives and CIOs, security was cited as the top concern for the adoption of cloud computing. Enterprises that plan to utilize cloud services for their infrastructure, platform, and/or software needs must understand the security risks and privacy issues related to cloud computing. This chapter discusses the technical, legal, and policy/organizational security risks of cloud computing, and reviews recommendations/strategies for managing and mitigating security threats in cloud computing. It also presents vendor-specific solutions and strategies that cloud service providers are implementing for mitigating security risks in cloud computing.