ECG findings are reported in 600 consecutive cases of diphtheria treated in an Army general hospital in Germany from Sept., 1945, to Dec, 1946 The series includes 26 cases of cutaneous diphtheria. Ages ranged from 18 to 43 yrs., avg. 23.4 yrs. 563 males and 37 females were seen in this series. Significant ECG changes were found in 143 cases (23.9%). The most frequent changes were decreased voltage or negativity of the T-waves. This does not substantiate the previous belief that P-R prolongation is the most common finding in such cases. The severity of clinical infection showed no correlation with severity and duration of ECG changes.