AbstractAs the recording method for the track address in the magnetic disk drive, the Gray code with redundancy (Gray‐like code) has been used so that nearly the correct value can be obtained even if the head is located close to the track boundary. This paper proposes a recording/reproducing method for the track address in the magnetic recording where the Viterbi decoding is applied to the Gray code record. The detection performance is evaluated by the theoretical analysis and the simulation. As a result, it is seen that the same or better performance compared to the conventional method can be obtained. By the proposed method, the area for the track address recording can be reduced to one‐half to two‐thirds the conventional method. This helps to increase the recording capacity and improve the maximum seek time.