Abstract: AIM To investigate the risk factors for slow coronary flow (SCF) phenomenon. METHODS We retrospectively analyzed 85,668 patients undergoing coronary angiography from September 2006 to June 2015. Patients with normal TIMI flow were selected as control. SCF was defined as TIMI flow 2. Logistic regression was used to analyze the risk factors of SCF. RESULTS Nine hundred and fifty-eight patients demonstrated SCF and the incidence of SCF was 1.1%. In patients with SCF, there were more smokers, lower heart rate and higher HDL, Apo-A1, Apo-B, cystatin C and C-reactive protein (CRP) serum concentration compared with those in patients with non-SCF (P<0.05, P<0.01). Using multivariate logistic regression analysis, we found that gender (OR=15.119, 95%CI 4.854-47.096, P<0.05), age (OR=0.934, 95% CI 0.879-0.974, P<0.05), smoking index (OR=1.002, 95%CI 1.0-1.003, P<0.01), heart rate (OR=1.045, 95%CI 1.01-1.081, P<0.05) and Apo-A1 (OR=14.472, 95%CI 5.446-38.455, P<0.05) were independent predictors of SCF. CONCLUSION Male, older age, smoking index, lower heart rate, reduced Apo-A1 and increased CRP are independent predictors of SCF.