Recently, many studies have attempted to utilize mobile nodes as resources in mobile grids. Due to their underlying restrictions such as intermittent communication disconnections, limited battery capacity, and so on, mobile nodes are less reliable than wired nodes for job processing. Therefore, it is imperative to find an enhanced job scheduling method to provide stable job processing for mobile grids. In this paper, we propose an efficient job scheduling method in mobile grids, which can determine the suitable number of replicas for a job based on resource (mobile node) information, node status, and access point information. In our job scheduling method, mobile nodes are divided into node groups, and the number of subjobs assigned to each node group is derived from the reliability and performance of the node group. Simulation results show that our scheduling algorithms can reduce the makespan of entire jobs in mobile grid environments compared with random-based job scheduling.