Non-alcoholic fatty liver disease (NAFLD) is an emerging cause of chronic liver disease, with coronary artery disease (CAD) as the main cause of death in NAFLD patients. However, correlation between the severity of liver steatosis and coronary atherosclerosis is yet to be understood. Here we aim to explore the correlation between controlled attenuation parameter (CAP) values and SYNTAX (Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score in adult patients with significant CAD, defined as ≥ 50% stenosis of the left main coronary artery, or ≥ 70% stenosis of the other major coronary arteries. A cross-sectional study was conducted on 124 adult patients with significant CAD who underwent coronary angiography. Transient elastography with CAP was used to assess liver steatosis severity, resulting in a mean CAP value of 256.5 ± 47.3 dB/m, with 52.5% subjects had significant steatosis (CAP value of ≥ 248 dB/m). Median SYNTAX score was 22. A statistically significant correlation was observed between CAP value and SYNTAX score (r = 0.245, p < 0.0001). The correlation was more pronounced in patients with prior history of PCI (r = 0.389, p = 0.037). Patients with high-risk SYNTAX score (> 32) had the highest CAP value (285.4 ± 42.6 dB/m), and it was significantly higher than those with low-risk SYNTAX score (0–22), with a mean difference of 38.76 dB/m (p = 0.006). Patients with significant liver steatosis should undergo periodic CAD assessment and lifestyle modification, especially those with severe liver steatosis.