We report two sisters with dysferlinopathy who manifested different clinical phenotypes. A 22-year-old female (patient 1) noticed of difficulty in running at the age of 13 years, and since then weakness of the lower extremities has progressed slowly. She had typical features of Miyoshi myopathy (MM); i.e., young adult onset, dominant involvement of calf muscles and markedly elevated serum creatine kinase (CK). Her 19-year-old sister (patient 2) first noticed of weakness in lower extremities at age 12 years. On neurological examination, she had proximally dominant muscle weakness, consistent with limb girdle muscular dystrophy type 2B (LGMD2B); serum CK level was also markedly elevated. On MRI study of muscle, patient 1 showed fatty degeneration of calf muscles, whereas patient 2 showed no abnormality in quadriceps and calf muscles. Immunohistochemistry of the muscle biopsy specimens using anti-dysferlin antibody showed deficiency of this protein in sarcolemma. There have been only a few reports of sibling cases of dysferlinopathy whose clinical phenotypes are different. These sibling cases may have important suggestion on the mechanism(s) of phenotypic variation of dysferlinopathy.