Eleven-hundred myasthenia gravis cases observed by the author in a period of 37 years are reviewed. The ratio of familial incidence was 4.23%. Transitory (neonatal) myasthenia in new-born babies should be separated from the familial cases. In familial myasthenia gravis both maternal and paternal line can occur. The majority of the cases are similar to the generalized, acquired myasthenia gravis, still there are some myasthenic familial congenital patients, too. Some rare instances are reported, among them a unique family with six sisters suffering from myasthenia gravis. Genetic line and HLA antigens' role are dealt with. Observation of familial myasthenia cases may contribute to the knowledge of the immunologic and clinicopathologic background of the disease.