In the last two decades, event - triggered control method is considered because of its advantages comprising decrease in data transmission rate, decrease in controller computational burden which is appropriate for limited communication resources and reduction in battery usage. In the event-triggered control data will be transmitted after the event. In this type of systems, an event detection unit calculus condition of event occurrence. This condition is determined such that it meets some requirements like a specific efficiency or system stability. So far, most event-triggered controllers recognize the event occurrence on the basis of system states but the system states are not always available. In this thesis, an event - triggered controller is proposed using state estimator mode controller. System states are estimated based on the measured outputs. The proposed method is presented to use event-triggered control for these systems using estimated state. Hence, without measuring system states, event triggered controller can be used. controller is provided. For observable systems, system states are calculated for each time point using state estimator. The event detector uses the estimation of states to determine the event. Also, to estimate the states of observable systems, Kalman filter is proposed. The use of the event-triggered control with the proposed method reduces data transmission rate and computational complexity. Due to the wide applications of nonlinear systems, the use of event-triggered control for a specific ltr" Key Words: Event triggered control , State e stimates , Event detection, Controller design