Aim: Myasthenia gravis (MG) is a relatively rare autoimmune neuromuscular disorder. Over the last fifty years there has been a trend towards an increase of its prevalence. Last Sardinian report indicated a prevalence rate of 11.1 per 100,000 (1994) and an incidence rate of 0.8 per 100,000/year (1982-1994). We aimed to update MG incidence and prevalence in the Sardinian. Methods: Patients with diagnosis of MG according to clinical, electrophysiologic and laboratory criteria (incl., anti-AChR and MuSK antibodies) were included. The study was conducted in the provinces of Sassari and Olbia-Tempio, northern Sardinia, over the period 1996-2010. Multiple sources of information were used and data merged into one dataset for statistical analysis. The study was approved by the local Ethical Committee (N. 993/CE/2012). Results: On prevalence day (December 31, 2010) 320 MG cases were living in the study area. The overall crude prevalence was 64.9 (95%CIs, 61.0-68.9) per 100,000 inhabitants: 67.4 for males and 62.6 for females. The mean annual incidence rate was 4.60 (95%CIs 1.77-7.43) per 100,000: 4.72 for males and 4.48 for females. Conclusion: Our results indicate a relevant increase in MG incidence and prevalence in northern Sardinia as compared to previous reports, placing this area at high risk for the disease. MG incidence and prevalence increased in women, and late-onset MG predominant in men Acknowledgments: Regione Autonoma Sardegna (Assess. Sanità, Igiene, Assist. Sociale).