Background: Assess the predictive value of clinical risk scores (PAMI, GRACE, and ACEFm scores) for predicting primary PCI procedural complications. Subjects and Methods: This study included 270 patients with pPCI -treated acute STEMI. Patients who received thrombolytic therapy or GP inhibitors before pPCI, history of CABG and insufficient data for calculating the scores were excluded. All patients were subjected to history, ECG, PAMI, Grace and ACEF risk scores calculation, transthoracic echo, and assessment of procedural complications [no reflow, distal embolization, coronary dissection, and vascular complication] during pPCI. Results: We find no-reflow incidence to be 35.2%, distal embolization to be 14.4%, coronary dissection to be 10%, and vascular complications to be 11.1%. In patients with no-reflow and coronary dissection, the PAMI, GRACE and ACEF scores were significantly higher (p < 0.001) with no significant difference in patients with distal embolization and vascular complication. Significant relationships have been established between age, HTN, DM, SBP, ischemic time, KILLIP class ≥ I, GP IIb/IIIa inhibitor, LVEF, PAMI, GRACE and ACEF scores with no-reflow incidence by univariate analysis. Age, ischemic time, HTN, DM, GP inhibitor, LVEF, GRACE score ≥ 142 and ACEF score ≥ 1.31, with sensitivity 63.2%, 67.4%, specificity 58.3%, 70.9%, AUC 0.620, 0.751, respectively (p = 0.001) were independent predictors of no-reflow. In univariate analysis, there were significant relations of age, DBP, Killip class ≥ I, PAMI, GRACE, ACEF scores with coronary dissection incidence. DBP, GRACE score ≥ 159 and ACEF score ≥ 1.35, with sensitivity 70.4%, 66.7%, specificity 72.8%, 63.4%, AUC 0.669, 0.653, and accuracy 72.6%, 63.7%, respectively (p = 0.010, p = 0.004) were independent predictors of coronary dissection. Conclusion: GRACE and ACEF, simple clinical risk scores, are independent predictors of primary PCI procedural complications, including no-reflow and coronary dissection in acute STEMI patients. However, PAMI risk score is not a predictor of these complications. Keywords: STEMI, pPCI, PAMI score, GRACE score, ACEF score, no reflow, coronary dissection, distal embolization.