BACKGROUND: For the diagnosis or evaluation of airway obstruction in bronchial asthma and chronic obstructive lung disorders, various parameters derived from the forced expiratory volume curve and maximal expiratory flow volume cutie have been used. Recently the peak expiratory flow(PEF) measured by the peak flow meter is widely used because of its simplicity and convenience. But there were still no data of the predicted normal values measured by the peak flow meter in Korea. This study was to obtain the predicted normal value of PEF and to know the accuracy of this value 18 predict FEV1. METHOD: The measurements of PEF by the MiniWright peak flow meter and several parameters derived from the forced expiratory volume and maximal expiratory flow volume curves by the Microspiro HI 501(Chest Co.) were done in 129 men and 125 women without previous history of the respiratory diseases. The predicted normal values of parameters according tc the age and the height were obtained, and the regression equation of FEV1 by PEF was calculated. RESULTS: The predicted normal values of PEF(L/min) were 2.45 Age(year)+1.36 Height(cm)+427 in men and -0.96 Age(year)+2.01 Height(cm)+129 in women. FEFmax derived from the maximal expiratory flow volume cutie was less than by 125 L/min in men art 118 L/min in women respectively compared to PEF. FEV,(ml) predicted by PEF was 5.98 PEF(L/min) 303 in men and 4.61 PEF(L/min) 291 in women respectively. CONCLUSION: The predicted normal value of PEF measured by the peak flow meter was calculated and it could be used as a standard value of PEF while taking care of patients with airway obstruction FEV1, the gold standard of ventilatory function could be predicted by PEF to a certain extent.