Mobile agents are an imminent technology for developing applications in mobile, distributed and pervasive computing. They offer a broad spectrum of features like autonomy; migrate to remote computers and process data to save remote connections. Mobile agents can be applied to a broad domain: network management, sensor network, grid computing, web services, and data mining. Numerous mobile agent systems have been developed, while some have been outdated and no longer in use others are in a continuous process of development, offering a variety of features. With the introduction of new computing platforms, to take advantage of mobile agent technology one must develop distributed applications that can cater to the needs. In this survey paper, we evaluate some of the existing mobile agent systems.