Three patients of myasthenia gravis, who under went video-assisted thoracoscopic surgery (VATS) were given general anaesthesia by propofol infusion and muscle relaxation by atracurium infusion. Isoflurane was added to control depth of anaesthesia on the basis of haemodynamic changes during surgery. One lung ventilation (OLV) was achieved by placement of Carlens left sided double lumen bronchocatheter. Right-sided surgical approach was used to perform thymectomy. Contrary to claimed short duration of surgery, in first patient, OLV lasted for 10 hours 30 minutes and patient developed re-expansion pulmonary oedema. OLV in second and third patient was for six hours thirty minutes and three hours 45 minutes respectively. Morning dose of pyridostigmine was omitted and atracurium (0.1 mg/kg) was found to be satisfactory for intubation and relaxation was maintained with atracurium infusion to get desired monitored effect. We could not extubate our patients due to longer duration of surgery and the sequelae there off. Post-operative elective ventilation and spontaneous weaning off the atracurium effect was thus preferred.