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Myasthenia gravis is an insidious disease characterized by fluctuating muscle weakness that worsens with use and improves with rest. It is caused by autoimmune antibodies that block nicotinic acetylcholine receptors causing decreased motor end-plate membrane potential and decreased neurotransmission. The initial symptoms are normally ocular (ptosis, diplopia). More generalized muscle involvement occurs in approximately 80% of patients. Proximal muscles are affected more than distal muscles. Respiratory symptoms include dyspnea (especially if supine) and decreased cough. Symptoms may be exacerbated by stress, infection, bright sunlight, and increases in temperature. The diagnosis is made by history, physical examination, and diagnostic testing (electromyography (EMG), edrophonium test). A patient with myasthenia gravis poses many potential issues for anesthesiologists depending upon the treatment the patient receives. Any treatment should be continued perioperatively and the use of neuromuscular blockers should be avoided if possible or tailored to the patient and the requirements of the procedure. It is important to remember that if acetylcholinesterase inhibitors are continued, the metabolism of ester local anesthetics, succinylcholine, and mivacurium may be decreased. Regional anesthesia may be preferable to general anesthesia due to avoidance of airway manipulation; however, an increased duration of action may be observed if ester local anesthetics are used. Premedications that may cause respiratory depression should be avoided. Patients with myasthenia have a variable response to succinylcholine depending on their medical therapy and succinylcholine is often avoided for this reason. Decreased doses of succinylcholine are needed if the patient is being treated with acetylcholinesterase inhibitors and patients may have a prolonged block or even phase II blockade. In patients not receiving therapy, increased doses are needed. Patients with myasthenia are extremely sensitive to nondepolarizing agents due to a decreased number of acetylcholine receptors. Decreased doses (10-50% of normal doses) of nondepolarizing agents should be used and long-acting agents should be avoided.