Background and Objectives: Heart failure (HF) is a threatening health condition that is associated with an increasing prevalence and high expenses because of frequent patient hospitalizations. The purpose of this study was to evaluate the factors that influence the length of in-hospital stay in HF patients.Materials and Methods: A total of 220 patients (43.2% men), admitted to the Department of Cardiology, Kaunas Hospital of Lithuanian University of Health Sciences from the 1st of January 2021 to the 31st of May 2021, were included in this study. According to the length of in-hospital stay, patients were stratified into two groups: the first group’s length of stay (LOS) was from 1 to 8 days, and the second group’s LOS was 9 days or more.Results: The median LOS was 8 (6–10) days. Multivariate logistic regression analysis revealed five predictors as independent factors associated with prolonged hospitalization. These predictors included treatment interruption (OR 3.694; 95% CI 1.080–12.630,p= 0.037), higher value of NT-proBNP (OR 3.352; 95% CI 1.468–7.659,p= 0.004), estimated glomerular filtration rate (eGFR) ≤ 50 mL/min/1.73 m2(OR 2.423; 95% CI 1.090–5.383,p= 0.030), systolic blood pressure (BP) ≤ 135 mmHg (OR 3.100; 95% CI 1.421–6.761,p= 0.004) and severe tricuspid valve regurgitation (OR 2.473; 95% CI 1.086–5.632,p= 0.031).Conclusions: Several variables were identified as significant clinical predictors for prolonged length of in-hospital stay in HF patients where treatment interruption, higher NT-proBNP value and lower systolic BP at admission were the most important.