Abstract: In the paper, a new self-tuning controller using the techniques of conditionally updating the parameter estimates for time-invariant linear systems with bounded disturbances is proposed. The major feature of the new controller is that although the computational effort required is approximately the same as that required by the classical self-tuning regulator, it has the tracking capability in addition. Besides, the controller described in the paper ensures BIBO stability in the presence of bounded disturbances. The theoretical analysis of system stability, the upper bounds of tracking errors and the boundedness of parameter estimates when using the algorithm proposed in the paper are given in detail. Simulation results of the comparisons in performance between the new controller and some existing controllers are also given.