Effects of a magnetic field on low-angle misorientation distribution and CSL boundary occurrence in ferrite in 42CrMo steel during the austenite to ferrite and pearlite transformation were investigated. The results show that a magnetic field can considerably lower the frequency of low-angle misorientations in ferrite lamellae and raise the occurrence of Sigma coincidence boundaries, especially Sigma3 in ferrite. But no obvious effect on crystallographic orientation distribution, or texture, was detected. (C) 2005 Springer Science + Business Media, Inc.