Background High Neutrophil-to-Lymphocyte Ratio (NLR), Monocyte-to-Lymphocyte Ratio (MLR), Platelet-to-Lymphocyte Ratio (PLR) were associated with worse prognosis of sepsis patients, but the relationship between NLR, MLR, PLR and mortality in sepsis patients with coronary artery disease (CAD) remains unclear. The purpose of this study was to explore the association between NLR, MLR, PLR and 28-day mortality in sepsis patients with CAD, and to evaluate diagnostic accuracy combining sequential organ failure assessment (SOFA) scores.Methods Our study was based on cross-sectional and 28-day in-hospital data obtained from the MIMIC-III database between 2008 and 2012. Clinical characteristics and laboratory test data has been collected from hospitalization record. The relationship between NLR, MLR, PLR and 28-day mortality in sepsis patients with CAD was examined using the Cox proportional hazards model. We applied Receiver operating characteristic (ROC) analysis for predicting 28-day mortality in sepsis patients with CAD by combining NLR, MLR and PLR with the sequential organ failure assessment SOFA scores.Results This study included 984 sepsis patients with CAD in total. Sepsis patients with CAD who had high NLR, MLR, and PLR had a higher risk of 28-day mortality. (All P < 0.05). The AUCs of NLR, MLR, PLR, and SOFA score were 0.609, 0.606, 0.594 and 0.676, respectively. Combining NLR, MLR, and PLR with SOFA scores increased the diagnostic accuracy of predicting 28-day mortality (AUC: 0.703).Conclusion High NLR, MLR and PLR were associated with 28-day mortality in sepsis patients with CAD.