est (RST) is the most commonly used electrodiagnostic test to asses the defect of neuromuscular transmission, which is reported to be positive in the diffuse and restricted ocular forms 60-95% and 14-50%, respectively. In a cross-sectional study, to determine the efficacy of repetitive stimulation test in myasthenia gravis, we evaluated the results in 30 cases who were hospitalized in Imam Khomeini Hospital during 1996-1999. Patients were first selected clinically and then confirmed by Tensilon test.Various clinical types including generalized and restricted ocular forms with different severity and duration were entered in this study. Considering the fact that the positiveness of the test is enhanced by assessment of more muscle groups, we evaluated decremental response in the facial, proximal and distal muscles of limbs. 90% of patients had the generalized form of the disease, whereas ocular myasthenia gravis was seen only in 10% of the cases. 74% of females and 73% of males showed positive response (overall: 73.3%). No Significant association was found between the positive response, and age and sex. Peaks of incidences of the disease for the males were in fourth and sixth decades and for the females in thired decades