This is a patient who was presented initially with symptoms of malaise, tiredness and exertional dyspnoea and found to have a severe normocytic normochromic anaemia with low reticulocyte counts. Bone marrow confirmed the diagnosis of pure red cell aplasia (PRCA) and at the time serology for recent parvovirus infection was positive. He was successfully treated with transfusions and intravenous Ig. Six years later, he had a mild relapse of his PRCA and subsequently developed severe dysphagia and dysarthria which were fatigable. Positive antiacetylcholine receptor antibodies confirmed the diagnosis of myasthenia gravis. The two conditions are both known to be associated with thymoma. Imaging and resection of the thymus gland showed only the presence of a thymic cyst. Treatment with pyrdistogmine and intravenous Ig have kept the patient asymptomatic and in remission. The rare association of the two autoimmune conditions associated in the same patient without thymoma is discussed.