Background <p>To determine the potential role of C-reactive protein (CRP)-albumin-lymphocyte (CALLY) index in predicting minimally-invasive direct coronary artery bypass (MIDCAB) outcomes.</p> Methods <p>This study included 124 consecutive patients who underwent MIDCAB surgery. Demographic properties of patients, CALLY index, operative parameters and post operative outcomes were recorded. Patients were stratified into quartiles based on their CALLY index values. For comparative analyses, the lower half (Q1–Q2) was designated as the low-CALLY group, and the upper half (Q3–Q4) as the high-CALLY group.</p> Results <p>Blood analyses revealed that patients in the higher CALLY group had significantly elevated albumin and lymphocyte levels and lower CRP concentrations (<i>p</i> &lt; 0.01 for all). CALLY index was significantly higher in the Q3–Q4 group (median: 2.7 vs. 0.5, <i>p</i> &lt; 0.001). Operative time was longer in the low CALLY index group (198.7&#xa0;min vs. 162.2&#xa0;min, <i>p</i> = 0.001). Among the operation time divisions, the time to reach the pericardium was similar between the groups, while preparation of vessels and anastomosis times were longer in the low CALLY group (<i>p</i> = 0.190, <i>p</i> = 0.001 and <i>p</i> = 0.009). Hospital length of stay was longer in the low CALLY group (<i>p</i> = 0.001). The complication rate was 27.4% in the low CALLY group and 9.6% in the high CALLY group (<i>p</i> = 0.011).</p> Conclusion <p>For the first time the present study found a significant relationship between higher CALLY index and shorter operation time, shorter hospitalisation time. Additionally, patients with lower CALLY index were significantly more vulnerable to postoperative complications following MIDCAB.</p> Trial registration <p>Not applicable.</p>