Myasthenia gravis is a rare disorder of autoimmune origin, caused by dysfunction of neuromuscular transmission. Clinically it manifested by a muscular weakness accentuated to the effort. We report the results of a retrospective study of 18 cases of myasthenia gravis in the department of neurology of the military hospital Moulay Ismail of Meknes during a period of 10 years. The sex ratio for our patients was 3.5. 67% of them were between 20 and 40 years old. The average deadline to diagnosis was two years. A personal history of Graves’ disease was present in 11% of our patients and type 1 diabete in siblings in 11% of cases. The inaugural symptoms were progressive in 50 % of the cases, affecting mainly the eye (94 %), the pharyngo-laryngeal region (67 %) the jaw (44 %), the roots of the members (33 %), the infringement of the respiratory muscles (22 % of the cases) and the fall of the head (6 %). The generalized form of the disease predominated at the time of diagnosis (67%), and the search for anti-acetylcholine receptor (anti-RAch) antibodies was positive in 89% of the cases. Thoracic imaging revealed thymoma in 33% of cases and thymic hyperplasia in 17% of cases. All patients received an acetyl cholinesterase inibitor. 33% of the patients in our series required a background treatment, consisting of corticosteroids alone (22%) or corticosteroids and immunosuppressive agents (11%). Thymectomy was performed in 56% of our patients