In this paper, we investigate the robust control problem of discrete event systems in a networked environment. In other words, we use a supervisor to control several possible plants (discrete event systems) to achieve given specifications when there are communication delays and losses in communication networks linking the supervisor and the plants. We translate the robust networked control problem into a conventional networked control problem by constructing an augmented automaton for all possible plants and an augmented specification automaton for the corresponding specification automata. We then solve the robust networked control problem. We consider two cases. The first case is when all the specifications are the same. For this case, we derive a necessary and sufficient condition for the existence of a robust networked supervisor. The second case is when the specifications are different, which is more general compared with the first case. In the second case, we can only obtain a sufficient condition for the existence of a networked supervisor. The results are illustrated by an example of customized products filling line.