Introduction: Epidemiological studies indicated that patients suffering from coronary slow flow phenomenon (CSFP) are predisposed to dyslipidemia. However, there are limited studies evaluating the relationship between atherogenic index of plasma (AIP), which is a novel indicator of atherogenic dyslipidemia, and CSFP. This study aimed to investigate the prognostic role of the AIP in predicting CSFP among patients with undergoing coronary angiography. Methods: This retrospective study included 110 patients with CSFP diagnosed by methods of Thrombolysis in Myocardial Infarction (TIMI)-frame count (TFC) and 110 controls with normal coronary flow (NCF). AIP obtained as the base 10 logarithm of the ratio of triglycerides to HDL. Results: Mean AIP level was higher in the CSFP group than NCF group (0.6 ± 0.2 vs. 0.4 ± 0.2, p < 0.001). Multivariable regression analysis showed that AIP level (OR = 15.33, 95% CI = 4.11- 57.18, p < 0.001), as well as neutrophil and platelets levels, were independent predictor of CSFP. The threshold value of the AIP in predicting CSFP was >0.7 with 64.5% sensitivity and 69.8% specificity (Area under the curve [AUC] = 0.714, p < 0.001). Conclusion: API was higher in CSFP patients and was determined as an independent predictor of CSFP. Prior to planned diagnostic coronary angiography, API exhibits significant diagnostic performance in predicting CSFP.