Distributed systems using mobile computing do not have the traditional ACID properties (Atomicity, Consistency, Isolation and Durability), and, therefore, consistency problems may occur. These problems may be managed by using semantic ACID properties, i.e. from an application point of view, the system should function as if all the traditional ACID properties had been implemented. In this paper the objective is to describe in detail how the global semantic atomicity property may be implemented in systems using mobile computing. How to implement the other global semantic ACID properties is described in Frank and Zahle (1998).