Hypokalemia in sheep causes cardiac arrhythmia and electrocardiographic changes such as changing the shape of QRS,complex and T wave and the distance between waves. In this study, 20 rams with the age of 12-15 months were divided into two groups. Electrocardiography was used to check the heart rhythm. After recording ECG and sampling, in order to create hypokalemia Isoflupredon acetat at a dose of 4mg was used intramuscularly in oll 10 treatment. All P waves in the control and the experimental group was recorded as positive and their monophasic or diphasic state was also studied. Between days 0 to 4, 30 cases of monophasic and 20 cases of diphasic P wave was recorded is the control group. In the treatment group, these figures were 21 and 29 cases respectively. Different shapes of QRS waves were seen  in both treatment groups .In the control group they were recorded as QRS in 10 cases, qrs in 15 cases and qRs in 25 cases with in the treatment  group it was QRS in 31 cases, Qrs in 1 case, qrs in 4 cases and qRs in 14 cases. By examining the ECG in the control group on days zero to 4th day, sinus arrhythmia and atrioventricular block was observed in 7 and 2 cases respectively and in the treatment group sinus arrhythmia, atrioventricular block, atrial premature contraction and sinus tachycardia was recorded in 14, 12, 3 and 5 cases respectively. The results indicated that various arrhythmias can be observed due to hypokalemia. As physiologic arrhythmias can lead to pathologic arrhythmias, the animals should be treated with anti-arrhythmia drugs.