A neural network adaptive force controller is proposed for a real hydraulic system. The dynamic model of this system is highly non-linear and very complex to obtain. Thus, it is considered as a black box, and a priori identification becomes necessary. A neural network is used to approximate the model, then controller using Lyapunov approach is designed. The neural network parameters are updated online according to an adaptation algorithm obtained via stability analysis. The performance of the proposed neural network controller is validated on an experimental plant.