In order to observe the arrhythmia which occured in early convalescent phase of acute myocardial infarction, a 24 hour ambulartory ECG monitiring was performed in 15 patients who is admitted at dept of Int Medicine, Ewha Womans University hospital from Aug. 1985 to Sept. 1986. during 7.5+/-3.4 days after admission. In all cases one or more of the following arrhythmias were observed;atrial premature beat, ventricular premature beat(VPB), transient paroxysmal ventricular thchycardia, atrial fibrillation, sinus arrest and junctional beat. Of 15 cases, 11(77.3%) had VPB's:Simple VPB's in 4 cases(26.7%) and complex VPB's(6.52+/-2.52)(P<0.05). But there were no difference of premature and abberancy index between complex VPB's and simple VPB's(P>0.1). In addition, we compaired the arrhythmias in CCU with those of early convalescent phase of acute myocardial infarction. But there was no correlation between them.