Background: Release of cytokines in sepsis can cause left heart failure and left ventricular systolic dysfunction (LVSD). In sepsis, there is a releasing of Procalcitonin (PCT) and tumor necrosis factor-α (TNF-α) because of the stimulation of cytokine pro inflammation affected by activated NF-kB. This study aimed to examine PCT as a predictor of LVSD in sepsis, the value of Area Under the curve (AUC), sensitivity, specificity, cut off point, and a probability of PCT and TNF-α as a predictor of LVSD, and then to identify the best diagnostic predictor of LVSD.Subjects and Method: This was a cross-sectional study. A sample of 71 sepsis patients aged >18 years old admitted to the intensive care unit (ICU) from November 2016 to March 2017was selected for this study. The dependent variable was left ventricle ejection fraction (LVEF). The independent variables were PCT and TNF-α. LVEF and diastolyc function were measured by transthoracic echocardiography. Data on PCT and TNF-α level were obtained from the medical record.Results: As many as 22 patients had mild sepsis (30.9%), 40 patients had severe sepsis (56.4%), and 9 patients had a septic shock (12.7%). The AUC value of PCT level was 0.81 (95% CI 0.71-0.91; p<0.001). The optimal cut-off point was ≥7.88 ng/mL and Diagnostic Odd Ratio (DOR) was 5.55. The AUC value of TNF-α level was 0.73 (95% CI 0.60-0.86; p= 0.002). Optimal cut off point was ≥7.36 pg/ml and DOR was 5.03. The multivariate analysis resulted that PCT was the best predictor of LVSD (AUC 0.70), and TNF-α (0.69). The combination of PCT + TNFα would increase diagnostic value with AUC 0.77.Conclusion: PCT was a better predictor of LVSD than TNF-α. This finding is significant since it will enable clinicians to easily diagnose LVSD by measuring PCT. The combination of PCT and TNFα was the best efficient diagnostic predictor of LVSD.Keywords: Left Ventricular Systolic Dysfunction, predictor, PCT, TNF-α Correspondence: Trisulo Wasyanto. Department of Cardiology and Vascular Medicine, Faculty of Medicine, Universitas Sebelas Maret. Jl. Ir. Sutami 36A, Surakarta 57126, Central Java. Email: trisulo.wasyanto@gmail.com.Indonesian Journal of Medicine (2018), 3(3): 139-145https://doi.org/10.26911/theijmed.2018.03.03.03