Background: A retrospective study was performed to study the effect of polycythemia on the severity of coronary artery occlusions and echocardiographic characteristics among acute coronary syndrome (ACS) patients in Yemen. Methods: Tow hundred and four (204) ACS patients in Yemen who underwent coronary angiography were reviewed from January 2014 to December 2014. Results: The mean age of Polycythemia ACS patients was significantly lower than normal hemoglobin patients (54.59 years vs. 57.08 years; p < 0.000). The prevalence of hyperlipidaemia for Polycythemia ACS patients was significantly higher (55.1% and 39.9%; p < 0.000). Also the prevalence of history of coronary artery disease (CAD) for Polycythemia ACS patients was significantly higher (21.3% vs.10.6%; p < 0.000). The prevalence of hypertension (HTN), diabetes mellitus (DM), and tobacco smoking were comparable at both groups. Left ventricle ejection fraction (LVEF) for Polycythemia ACS patients was significantly lower (47.9% and 52.8%; adjust; p < 0.000). Normal coronary angiography for non-Polycythemia ACS patients was non-significantly higher (9.6% vs. 7.6%). Single vessel occlusion for non-Polycythemia patients was higher (41.9% vs. 29.6%). Two vessel occlusions were comparable for patients at both groups. Three vessel occlusions for Polycythemia ACS patients were significantly higher (37.2% vs.23.6%). Conclusions: Acute coronary syndrome occurs at a younger age for Polycythemia ACS patients. Polycythemia ACS patients are also more likely to have hyperlipedaemia and history of CAD. Impaired LVEF occurs more commonly in Polycythemia ACS patients. The ACS patients who have Polycythemia were associated with more coronary arteries occlusions. Three vessel occlusion and circumflex coronary artery occlusions occur more commonly among Polycythemia ACS patients. We noted association between high percentages of hemoglobin and coronary complications.