Corticosteroids has been used in treatment of wide varieties of disease, but there was no report which related to the effects on cardic function with the long term corticosteroids therapy in children. We had been evaluated 18 patients with nephrotic syndrome who were admitted to department of pediatrics, Kyung Hee University Hospital until March 1987. Also we examined interventricular septal thickness, left ventricular posterior wall thickness and all parts of internal dimension of heart, and cardiac output and STI(Systolic Time Interval) by M-mode and Doppler echocardiography, and compared with body surface matched control group. Result are as follows;age and sex distribution were 4 4/12 to 14 6/12(9.11+/-3.55 years) and 15 males and 3 females. The duration of follow up was from 6 to 132 months(39.28+/-36.12 months). The interventricular septal thickness and left ventricular posterior wall thickness were more thickened in corticosteroids group than those of control. Systolic time interval, the index of left ventricular function, was more increased in corticosteroids group than in control group, but there was no differences in cardiac output between two groups. lthough longterm follow up studies are needed to confirm the cardiac effects of long term corticosteroids therapy, we conclude that long term corticosteroids therapy cause significant hypertrophy of cardiac muscle and periodic evaluation of cardiac function such as noninvasive Doppler echocardiographic studies are mandatory in patients with long term corticosteroids therapy.