Objectives: To determine frequency of left main stem (LMS) and triple vessel coronary artery disease (3VCAD) in patients of Non-ST-elevation myocardial infarction (NSTEMI) and to compare the frequency of LMS and 3VCAD in patients with NSTEMI with or without ST elevation in lead aVR. Methodology: Total 346 patients with NSTEMI having age 30-70 years were included in this descriptive cross-sectional study. The data on demographic details was collected. All patients underwent electrocardiography (ECG) and cardiac specific troponin-I assessment. Patients were categorized as NSTEMI with or without ST-elevation in lead aVR. Coronary angiography was performed in all patients and angiographic findings were noted. Results: Mean age of patients was 51.87±10.03 years. There were 218 (63.01%) males and 128 (36.99%) female patients. 182 (52.60%) patients of NSTEMI had ST elevation in aVR. LMS disease was found in 53 (29.10%) patients with ST elevation in aVR. Sensitivity, specificity, positive predive value and negative predictive value of ST elevation in aVR for LMS disease was 62.35%, 50.57%, 29.12% and 80.49% respectively. 3 VCAD was found in 54 (29.70%) with ST elevation in aVR. Sensitivity, specificity, positive predive value and negative predictive value of ST elevation in aVR for 3VCAD was 77.14%, 53.52%, 29.67% and 90.24% respectively. Conclusion: NSTEMI patients with ST elevation in aVR may have higher chances of having LMS disease or 3VCAD. There is high negative predictive value for ST elevation in aVR to predict LMS disease or 3VCAD.