A recent study reported an association between left-handedness and some pathologies, such as autoimmune diseases, including myasthenia gravis (MG). We studied hand preference in 102 patients with a generalized autoimmune form of myasthenia gravis and in a control group of 178 subjects. We employed Oldfield's inventory with a few minor modifications. The questionnaire also asked the hand preference of patients' and controls' relatives. For each subject, the laterality quotient (LQ) was calculated and submitted to ANOVA. The frequency of left-handedness in controls was similar to that reported in the literature. Although left-handedness occurred less often in myasthenics, the difference between the two groups was not significant. Also the frequency of left-handedness in relatives of myasthenic patients did not differ from that observed in controls.