BACKGROUND: In most studies, the agreeable risk scores for ST-elevation myocardial infarction (STEMI) consist of thrombolytic in myocardial infarction (TIMI) risk score and modified Gensini risk score. Researchers showed significant relations between TIMI with angiography scores in patients with UA/NSTEMI. We studied this relation in patients with STEMI. METHODS: We studied CCU patients with STEMI hospitalized in several hospitals of Isfahan, Iran from September 2007 to June 2008. Sampling method of 240 patients was random and simple. Exclusion criteria were incomplete history, nonspecific electrocardiogram changes, left bundle branch block and not accomplished angiography or accomplished angiography after 2 months of STEMI. Questionnaire indices collected on the basis of TIMI (0-14 points). Echocardiography and angiography were done and then, we used Gensini (0-400 points) to review films of angiography. Spearman`s rank test and Pearson correlation coefficient were used to study the relation between these scores. RESULTS: One hundred and sixty one patients were male and their average age was 60.02 years. Averages of TIMI and Gensini scores were 6.30 ± 2.5 and 120.77 ± 50.4, respectively. Study showed significant relation between TIMI, age and LVEF (P <0.001, r=-0.46). Also, between Gensini and age, gender and LVEF significant relation was found (P <0.001). But, a meaningful correlation didn’t exist between TIMI and the gender (P =0.08). Our study proved direct relation between TIMI risk scores and modified Gensini scores (P <0.001, r=0.55). CONCLUSION: We may decide quickly and correctly in emergency room to distinguish which patients with STEMI could derive a benefit from invasive strategies using TIMI score. Also, TIMI risk score can be a good predictor to determine the extension of coronary artery disease in patients with STEMI. As a result, we suggest determination of TIMI score for any patient entered emergency room. Also, this score should be recorded at the time patient’s discharge. Keywords: TIMI Risk Score, Modified Gensini Risk Score, LVEF, STEMI.