Background: Acute myocardial injury and heart failure characterized by elevated cardiac troponin and decreased heart pump function are significant clinical features and prognostic factors of coronavirus disease-19 (COVID-19). Triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio is an indicator of insulin resistance. This study aimed to explore the association of the TG/HDL-C ratio with cardiovascular risk and prognosis in COVID-19. Methods: Ninety-eight laboratory-confirmed patients with COVID-19 admitted in a tertiary teaching hospital in Wuhan, China, were enrolled in this retrospective study. Regression models were used to investigate the association between TG/HDL-C ratio with myocardial injury, heart failure, severity, and mortality in COVID-19. Results: Among the 98 patients, the mean age was 63.9 +/- 1.4 years, and male sex (58, 59%) was predominant Forty-six patients (47%) were admitted to the intensive care unit (ICU), 32 (33%) and 46 (47%) patients suffered from myocardial injury and heart failure, respectively, and 36 (37%) patients died. The TG/HDL-C ratio was increased in patients with myocardial injury, heart failure, severe illness, and fatal outcome (P<0.05 for each). Baseline TG/HDL-C ratio significantly correlated with log transformed levels of plasma high-sensitivity cardiac troponin I (r=0.251, P=0.018), N-terminal brain natriuretic propeptide (r=0.274, P=0.008), glycated hemoglobin (r=0.239, P=0.038), and interleukin-6 (r=0.218, P=0.042). Multivariate logistic regression analysis showed that an increased TG/HDL-C ratio was independently associated with the risk of myocardial injury [odds ratio (OR)=2.73; P=0.013], heart failure (OR=2.64; P=0.019), disease severity (OR=3.01; P=0.032), and fatal outcome (OR=2.97; P=0.014). Conclusion: Increased TG/HDL-C ratio was independently associated with myocardial injury, heart failure, disease severity, and mortality in patients with COVID-19, and it may be a useful marker for early identification of patients with high risk and poor outcome.