Moon and Bien (1991) proposed a new accommodation filter for the state estimation and the failure diagnosis, and in addition a minimum variance accommodation filter was suggested for the stochastic system. However, in the above paper the design of the filter for the deterministic system was heuristic, whereas for the stochastic system the gain used was not a minimum variance filter gain. In this correspondence item we present a systematic method of gain determination for the accommodation filter as well as a minimum variance filter gain for the noisy system.