Effective risk stratification is integral to the management of patients with acute coronary syndromes. This prospective study was done to evaluate the association between on-admission renal function and in-hospital outcome of patients with acute ST segment elevation myocardial infarction (STEMI). This study was carried out in the department of cardiology, NICVD, Dhaka, Bangladesh during the period from January 2004 to December 2004. Total 90 patients with first episode of acute STEMI were grouped according to renal function. Group I patients had normal renal function and Group II patients had renal impairment. Among group I patients, only 3.7% had Killip class IV heart failure, whereas among group II patients, 19% had Killip class II and 6.3% had Killip class IV heart failure (p<0.001). Mean percent of LVEF was significantly higher in Group I patients (52.0±5.2 vs. 47.9±6.3, p<0.01). Ventricular tachycardia occurred in significantly higher proportion in group II patients (7.4% vs. 63.5%, p<0.001). It was concluded that some in-hospital complications of acute STEMI were significantly higher and others were more prevalent in patients who had associated renal impairment compared to those who had normal renal function. This study can develop a clinical prognostic tool, which is simple, cheap and easily be applied at bedside. Concentrating on aggressive management of such patients may reduce their morbidity and mortality.