The reliable execution of a mobile agent is a very important design issue to build a mobile agent system and many fault-tolerant schemes have been proposed. Hence, in this paper, we present FATOMAS , a java-based fault-tolerant mobile agent system based on an algorithm presented in an earlier paper . In contrary to the standard "place-dependent" architectural approach, FATOMAS uses the novel agent-dependent approach introduced in the paper. In this approach, the protocol that provides fault tolerance travels with the agent. This has the important advantage to allow fault-tolerant mobile agent execution with out the need to modify the underlying mobile agent platform. We derive the FATOMAS (Fault-Tolerant Mobile Agent System) design which offers a user transparent fault tolerance that can be activated on request, according to the needs of the task, also discuss how transactional agent with types of commitment constraints can commit. Furthermore this paper proposes a solution for effective agent deployment using dynamic agent domains.