The no-reflow (NR) phenomenon is frequently encountered in acute coronary syndrome. We evaluated the association between anticoagulation and risk factors in atrial fibrillation (ATRIA) and modified ATRIA risk scores and NR in ST-elevation myocardial infarction (STEMI). Consecutive patients (n = 551) who underwent primary percutaneous coronary intervention between December 2019 and June 2020 due to STEMI were included. The mean age of the patients was 60.5 ± 10.8 years (n = 369, 67% male). The ATRIA and modified anticoagulation and risk factors in atrial fibrillation-hyperlipidemia, smoking, male (m-ATRIA-HS) scores were calculated. The NR group had higher frequency of diabetes mellitus (DM), serum creatine kinase-MB (CK-MB) levels, and corrected thrombolysis in myocardial infarction frame count (cTFC) ( P = .002, P = .006, and P < .001, respectively). In regression analysis, ATRIA, m-ATRIA-HS, thrombus grade, and cTFC were independent predictors of NR. Age, higher CK-MB, and neutrophil-to-lymphocyte ratio and DM were the other predictors for NR. Pairwise comparison of receiver operating characteristics curve analysis showed that the m-ATRIA-HS (>2, area under curve [AUC]: 0.715) has better performance than ATRIA score (>1, AUC: 0.656), with a P < .022 and z statistics 2.279. In conclusion, ATRIA, especially the m-ATRIA-HS, can be used to evaluate NR risk in STEMI.