Background: Elevated Low density Lipoprotein (LDL) levels have been traditionally associated with development of atherosclerotic coronary artery disease (CAD). As LDL-cholesterol levels are not always raised in acute coronary syndrome (ACS) patients, sd-LDL is an emerging risk factor. The purpose of the present study was tri-fold. Firstly, it aimed to investigate the association of sd-LDL as a risk factor in ACS patients. Secondly, it aimed to correlate the presence of sd-LDL with severity of coronary artery disease as determined by coronary angiography. Lastly, it aimed to correlate the presence of sd-LDL with short-term outcomes.Methods: This was a prospective, hospital-based, cross-sectional, case-control study conducted over a 1-year study duration. Patients above the age of 18 years diagnosed with ACS within 24 h of admission were studied. Blood samples were collected after all patients had undergone coronary angiography and sd-LDL levels were measured.Results: ACS patients had significantly higher sd-LDL levels than non-ACS patients (16.10 ± 1.42 mg/dL vs. 12.67 ± 0.71 mg/dL, P = 0.036). Males had significantly higher sd-LDL levels than females (16.79 ± 1.55 mg/dl vs. 10.77 ± 2.62 mg/dl, P=0.047). Patients with non-left anterior descending coronary artery (LAD) involvement had significantly higher sd-LDL levels compared to patients with LAD involvement (21.92 ± 3.55 mg/dL vs. 14.03 ± 1.35 mg/dL, P = 0.007). Conclusion:These results suggest that sd-LDL is a risk factor for the development of ACS in an Indian population.