Inflammation was detected in 9 of 13 patients with different phenotypes of dysferlin myopathy. Endomysial or perivascular infiltrates consisted of 11.1% ± 6.6% CD8⁺ cells, 40.6% ± 22.8% CD4⁺ cells, 36.7% ± 23.7% macrophages, and no B cells. Major histocompatibility complex class I was not upregulated in normal muscle fibers. In young patients with sporadic proximal weakness, very high creatine kinase levels, necrotic fibers and inflammation in the muscle biopsy, a diagnosis of dysferlin myopathy should be considered.