Abstract Background: Primary percuteneous coronary intervention (PPCI) is the prefered strategy for acute ST segment elevation myocardial inferction (STEMI). CAD is a diffuse process and patients presenting with a coronary syndrome in 20- 40% of cases have multiple significant coronary lesions, which confer a substantially increased risk of cardiovascular morbidity and mortality. Recent studies suggest that acute coronary syndromes, including AMI, may result from a systemic inflammatory process, causing multiple unstable lesions. Thus, a strategy of multivessel PCI in the peri-infarct period may be important in improving the outcomes of primary angioplasty. Such an attempt of complete revascularization may prevent recurrent ischemia from ‘non-infarct-related’ lesions, obviating the need for repeat angiography and intervention, and also possibly improves the late outcome by reducing the ischemic burden following myocardial damage. Contemporary guidelines recommend dilating only the infarcted related artery (IRA) during the urgent procedure, leaving the other stenosed vessels untreated "culprit-only revascularisation" (COR) or to dilate during a second elective procedure (staged revascularisation). Simultaneous treatment of IRA and non-IRA is recommended only in patients with cardiogenic shock. However, these guidelines are based on the results of earlier studies. With advancing technology and newer antiplatelet drugs, outcomes have improved even in patients undergoing multivessel and higher-risk elective procedures. Therefore, the optimal management of patients with multivessel disease in this setting still unclear. Aim of the Work: to compare between primary PCI for culprit lesion only and that for both culprit and non culprit lesion in ST segment elevation MI patients with multi-vessel disease. Patients and methods: this study concluded 50 patients with acute ST segment elevation myocardial infarction (STEMI) eligible for primary PCI and the patients were devided into two groups: 1st group: 25 patients were managed by primary percutaneous coronary intervention for infarct related artery only "culprit only revascularization" (COR). 2nd group: 25 patients were managed by primary percutaneous coronary intervention for infarct related artery and non infart related artery "total revascularization" (TR). All patients had done transthorthic echocardiography during admission and after six months to assess ejection fraction. Results: During follow up period 52% of patients in COR group had recurrent angina and chest pain while in TR group 36% of the patients had recurrent angina and chest pain with p-value 0.039. In culprit only revascularization group contrast induced nephropathy occur in 12% of patients while in total revascularization group 36% had contrast induced nephropathy with p-value 0.047. In culprit only revascularization group the mean LVEF was 50.40+ 3.18 while in total revascularization group the mean left ventricular ejection fraction (LVEF) was 51.36+4.37 with p-value 0.155. Conclusios: Total revascularization can be done in primary PCI in selected cases (simple lesion, low thrombus burden), which is safe and less expensive than culprit only revasvularization by reducing the possibelity of further unplaned procedures.