The blood glucose level at admission indicates (with some limitations) poor prognosis and thrombus burden in patients with the acute coronary syndrome (ACS). Our study aimed to measure the predictive value of the stress hyperglycemia ratio (SHR), an indicator of stress hyperglycemia, showing increased thrombus burden in patients with ACS. Patients (n = 1222) with ACS were enrolled in this cross-sectional study. Coronary thrombus burden was classified as high and low. SHR was calculated by dividing the admission serum glucose by the estimated average glucose derived from HbA1c. Low thrombus burden was detected in 771 patients, while high thrombus burden (HTB) was detected in 451 patients. SHR was found to be significantly higher in patients with HTB (1.1 ± .3 vs 1.06 ± .4; = .002). SHR was determined as a predictor of HTB (odds ratio (OR) 1.547 95% CI (1.139-2.100), < .001) as a result of univariate analysis. According to multivariate analysis, SHR was determined as an independent risk factor for HTB (OR 1.328 CI (1.082-1.752), = .001). We found that SHR predicted thrombus burden with higher sensitivity than admission glucose level in patients with ACS.