Abstract: AIM To discuss the relation between red cell distribution width (RDW) and severity of coronary artery disease. METHODSEnrolled in this study were 219 consecutive patients who had coronary angiography, including 118 patients with unstable angina pectoris (UAP), 52 with ST segment elevation myocardial infarction (STEMI) and 49 with non-ST segment elevation myocardial infarction (NSTEMI). The levels of RDW and N-terminal pro-brain natriuretic peptide (NT-ProBNP) were measured. The patients were divided into two groups according to SYNTAX scores: low score group (≤32; n=139) and high score group (>32; n=80). The relation between RDW and the severity of coronary artery disease was measured by Pearson correlation analysis. RESULTSRDW in high score group was higher than that in low score group ［(13.7±0.9)% vs.(12.4±1.4)%, P<0.05］. Pearson correlation analysis indicated that RDW was positively related to SYNTAX score (r=0.252, P<0.01). RDW in NT-ProBNP rising group was significantly higher than in NT-ProBNP normal group. CONCLUSIONRDW was significantly related to SYNTAX score.