Abstract: The joint design problem of the variable sampling interval and multiple state observers was studied. The network-induced delay was considered which could be larger than one sampling period, and the sampling period was assumed to be switched in a finite set. The Markovian jumping models of the networked control systems with multiple state observers and single state observer were constructed, based on which, the sufficient conditions for stochastic stability and optimal H∞ norm bound were derived for the closed-loop networked control systems by the application of Markovian theory. Furthermore, the controllers and observers were designed in terms of linear matrix inequalities (LMIs) technology. Simulations were compared to show the effectiveness of multiple state observers for networked control systems.