Background: We aimed to investigate the relationship between hemoglobin A1c (HbA1c) and coronary thrombus load in type-2 diabetes mellitus (T2DM) patients with non-ST segment elevation myocardial infarction (NSTEMI). Materials and Methods: Ninety diabetic patients with NSTEMI were recruited for the study. They were separated into two groups according to HbA1c levels. Forty-seven patients having HbA1c ≤6.5% formed Group-I (35 male, mean age 58 ± 10.5 years) and the remaining 43 patients with HbA1c >6.5% formed Group-II (23 male, mean age 58 ± 11.1 years). Both the groups were evaluated in terms of thrombolysis in myocardial infarction (TIMI) thrombus score and Syntax score. Results: Baseline patient characteristics were comparable in both the groups. TIMI thrombus score and Syntax score were higher in Group II than in Group I (3.2 ± 1.4 vs. 4.7 ± 0.5 and 20.2 ± 3.4 vs. 26.3 ± 3.0 respectively, P < 0.05). No significant difference was found in other parameters. In stepwise linear regression analysis, prepercutaneous coronary intervention (PCI) and post-PCI TIMI frame number and HbA1c were significantly related to the coronary thrombus scale. However, no significant relationship has been found between thrombus formation and hypertension, previous PCI history, pre-PCI heart rate, pre-PCI cholesterol status, and high-sensitive troponin T. Conclusion: In NSTEMI with T2DM, increased HbA1c (HbA1c >6.5%) is related with coronary thrombus in the target vessel. In those patient population, strict anticoagulation should be considered to prevent potential adverse events. [ABSTRACT FROM AUTHOR]