This paper presents an indirect adaptive control scheme that rejects unknown multiple narrow-band disturbances in hard disk drive systems. The proposed algorithm first finds the model of the disturbance (the internal model) and then adaptively estimates its parameters. The design of a band-pass filter with multiple narrow pass-bands is then presented and used to construct a disturbance observer (DOB) for disturbance rejection. The proposed algorithm estimates the minimal amount of parameters, and is computationally simple. Evaluation of the proposed algorithm is performed on a benchmark problem for HDD track following.