We have retrospectively analysed the records of patients diagnosed as having myasthenia gravis and followed up in our department from February 1973 to March 1995. The main clinical findings were ptosis, diplopia, dysphagia, dysphonia or dysarthria, mastigatory impairment, dyspnea, asthenia, weakness of the cervical muscles and of the extremities, as well as findings of the physical and neurological examination. Based on the information collected, the patients were classified clinically according the modified Osserman-Gerkins scale, but considering the non-dynamic aspects of that scale, we used the modified functional scale of Niakan and classified the patients clinically as follows: remission, controlled, stable, partially controlled, poorly controlled, no response. We collected 153 patients, 104 (68.0%) females and 49 (32.0%) males producing a female/male ratio of 2.2:1. The duration of the disease varied from seven days to 27 years, mean 6.26 years (+/- 5.44). Age at the first symptoms varied between 24 hours to 80 years, mean of 32.13 years (+/- 19.48). We had 30 patients ranging from 0 to 15 years of age, 91 patients were observed between 15 and 50 years and 32 patients after the age of 50 years. Above the age of 60 years, the disease aflicts males more than females with a ratio of 1.5:1. The acquired autoimmune form with generalized weakness was the most frequent presentation. However, ocular muscle weakness with ptosis and diplopia were the most common clinical presentation in our series.