In this letter, we investigate the iterative detection/decoding algorithms for two-track partial response channels.We first describe the iterative algorithm as an iterative message-passing/processing algorithm over a high-level normal graphand then propose two trellis-based detection algorithms. Thenatural one is based on a joint trellis, which can be implementedfor low-order channels. For moderate-order channels, we proposea separated detection, which is based on two single-track trellises.Compared with the joint detection, the separated detection issimpler in most cases. Simulation results show that, for two-trackEPR4 channels with minor intertrack interferences, the separateddetection causes only marginal degradation in performance.