One Stizostedion vitreum, obtained from Wood Lake, exhibited a generalized muscular anomaly. Gross examination of a fillet revealed myopathy typical of myo-fibrogranuloma, as described by Economon (1970). Myo-fibrogranuloma as characterized by extensive hypertrophy of trunk musculature with muscle fibers in various stages of dystrophy. Abnormal trunk tissue was histologically examined using representative sections stained with hematoxylin and eosin. North Dakota walleye myopathy is compared pathologically to the previously described walleye muscle disorder. The etiology of the dystrophy will be examined although the precise causative factors are unknown. This is the first report of myo-fibrogranuloma in North Nebraska. It was previously described in Minnesota and Nebraska. Walleye is the only piscine species known to exhibit this myopathy.