Virtualization has become a very popular research topic in recent years. Virtualization is used in varied applications such as e-Learning, business-to-business communication, social networking, computer simulation and enterprise development. These advances are due to the availability of high-speed computers, fiber-optic-enabled internet connections and advanced virtualization programs. However, only a very small amount of research has been conducted, most especially on the performance of virtualization programs. Thus little is known about the performance of the various virtualization programs such as VMware Workstation and VirtualBox. When dealing with virtualization, performance is of primary importance. This thesis reports on the performance of different virtualization programs, such as VMware Workstation 7 and Oracle VM VirtualBox 4 using MS Windows 7 guest-and host-operating systems. The chosen research methodology for this research is a mixed research methodology based on both qualitative and quantitative. A mixed research methodology allows the researcher to easily collect primary data via qualitative methods and then analyze the data using quantitative methods. The main purpose of this study is to find any performance differences in between VMware Workstation and VirtualBox based on Windows 7 guest and host OSs. Various experiments were conducted regarding the performance of VMware Workstation, VirtualBox and Microsoft Windows Virtual PC using Windows 7 and Linux Mint guest OSs and Windows 7 host OS. Findings of the experiments revealed that there are performance differences among VMware Workstation, VirtualBox and Virtual PC. In virtualization, it is generally thought that VMware Workstation is superior to other virtualization programs. However empirical results obtained from this study show that the performance of VMware Workstation and VirtualBox are similar. VMware Workstation has many features but its performance is not very different from VirtualBox. Virtual PC on the other hand is not a reliable product for serious virtualization as it lacks features, performance and support for different host and guest OSs. The overall findings of this study show that VMware Workstation and VirtualBox both meet performance and feature requirements for creating reliable virtual environments. This study opens a new path for research in the area related to performance of virtualization programs. Data gathered from this study was used to make meaningful conclusions in Chapter 6. The conclusion explores possible directions for future research on the performance of virtualization programs. Findings of this study may help businesses to select appropriate virtualization program as part of their information technology infrastructure and thereby benefit from using virtualization technology.