Because of the explosion in data growth, the requirement for high-density storage systems has increased. Bit-patterned media recording (BPMR) is a candidate for the next-generation magnetic recording systems, and its many advantages facilitate the achievement of recording densities of 1 Tb/in ² and beyond. In BPMR, each information bit is represented by a magnetic island; however, due to the small spacings between the along- and across-track islands that are for the achievement of a high areal density, severe extents of the inter-symbol interference and inter-track interference appear. These error factors degrade the system performance of the recording system. In this paper, an iterative channel detection scheme with a low-density parity check (LDPC) product code for which the extrinsic information between the soft output Viterbi algorithm and the LDPC product code is used for the BPMR is proposed. For the improvement of the BPMR performance, the modified extrinsic information data are exploited.