Background: A systematic review of literature published between 1980 and 2007, on the incidence of myasthenia gravis, was undertaken. Methods: All relevant papers found through searches of Medline, Embase and Science Direct were critically appraised and an assessment was made of the reliability of the reported incidence data. Results: Thirty-one studies were included in the review, the majority of which investigated populations in Europe. The incidence rates reported were between 3.0 and 30.0/1,000,000/year. However, it is thought that the rates at the upper end of this range, reported by the prospective studies, provided the most accurate estimates. Overall, incidence rates have increased over time owing to a greater awareness of the disease and improved methods of diagnosis. Conclusions: The most accurate estimate of incidence of myasthenia gravis was around 30/ 1,000,000/year. The incidence in children and adolescents aged 0–19 years was found to be between 1.0 and 5.0/ 1,000,000/year. The rates presented in this review are likely to be an underestimate of the true incidence rates, as mild cases will have been missed and cases in the elderly will have been misdiagnosed.