A novel input–output linearization minimum sliding mode error feedback control (I/OMSMEFC) is proposed for the synchronization between two uncoupled FitzHugh–Nagumo (FHN) neurons with different ionic currents and external electrical stimulations. To estimate and offset the system uncertainties and external disturbances, the concept of equivalent control error is introduced, which is the key to utilization of I/OMSMEFC. A cost function is formulated on the basis of the principle of minimum sliding mode covariance constraint; then the equivalent control error is estimated and fed back. It is shown that the proposed I/OMSMEFC can compensate various kinds of system uncertainties and external disturbances. Meanwhile, it can reduce the steady-state error more than the conventional sliding mode control (SMC). In addition, the sliding mode after the I/OMSMEFC will tend to be the ideal SMC, resulting in improved control performance and quantity. Sufficient conditions are given based on the Lyapunov stability theorem and numerical simulations are performed to verify the effectiveness of presented I/OMSMEFC for the chaotic synchronization accurately.