Abstract. Mobile Ad-Hoc Networks, or MANETs, provide communication between free-roaming mobile hosts without a fixed infrastructure. These MANETs operate under conditions of limited battery power and may also experience frequent network partitioning. This paper introduces a data replication technique called REALM (REplication of data for A Logical group based MANET database). REALM takes advantage of application semantics when determining where to place replicas of data items. It also tries to predict network partitioning and disconnection ahead of time and creates copies of data items accordingly. Experiments show that REALM increases the percentage of successful transactions with or without the presence of network disconnection and partitioning.