In this paper, a new method for maneuvering target tracking (MTT) based on nonlinear input estimation (IE) is innovated and is employed for tracking of maneuvering targets. Proposed method augments the states and unknown inputs (maneuvers) in a higher order state space realization and estimates both of them simultaneously. The concurrent estimation of states and inputs eliminates the maneuver detection delay which is popular in the conventional IE methods. The proposed method has excellent performance for both maneuvering and non-maneuvering stages. Also, a model with highly nonlinear dynamics for maneuvering targets is given and is used in the numerical simulations to analyze the performance of the proposed maneuvering target tracking method. Furthermore the proposed method is compared with a conventional IE method and the simulation results show the effectiveness of the proposed method.