Myasthenia gravis (MG) is an immune-mediated disorder characterized by fluctuating fatigue of skeletal muscles, often involving extrinsic ocular or bulbar districts. Myasthenia gravis in the elderly is an under-recognized condition, sometimes confused with cerebrovascular disease. Here we present a case series of myasthenia patients which onset was characterized by sudden dysarthria, clearly raising this diagnostic dilemma. In the workout of sudden onset isolated dysarthria, MG should be always considered. In fact, even if myasthenia is a rare condition, lacunar stroke only with this clinical presentation is also unusual, and significant risks may arise (e.g., unexpected myasthenic crisis).