Objectives: Healthcare-associated infections (HAIs) are persistent problem in contemporary in-hospital patients’ treatment but they are recognized as potentially preventable. The influence of HAI on patients’ outcomes after discharge is not fully acknowledged. The authors conducted the study to determine the associations between HAI and length of hospitalization, all-cause in-hospital death, need for treatment in the intensive care unit (ICU), and rehospitalization within 14 days, 30 days, and 365 days. Material and Methods: On the basis of inclusion criteria, 631 of 5322 (11.86%) inpatients were enrolled to the study, for whom the authors determined, among other factors, medical history, Activities of Daily Living (ADL) score and Nutritional Risk Screening 2002 (NRS-2002) score, nutritional status (using anthropometric characteristics and bioelectrical impedance analysis), and Charlson Comorbidity Index score. Results: Healthcare-associated infections occurred in 17.9% of the inpatients enrolled to the study. Healthcare-associated infections were linked with greater length of in-hospital stay (LOS), risk of in-hospital death, transfer to the ICU, and hospital readmission within 14 days and 30 days. In multivariate analysis, HAI was the strongest risk factor for LOS prolongation, need for treatment in the ICU (OR = 15.26, 95% CI: 3.0–77.8, p < 0.01), and all-cause in-hospital death (OR = 10.73, 95% CI: 3.9–29.69, p < 0.001), alongside NRS-2002 and ADL scores. Healthcare-associated infections did not affect the risk of 14- and 30-day and 1-year readmissions in multivariate analysis, which were related to, among other factors, ADL score and mode of admission. Conclusions: Healthcare-associated infections statistically and significantly affected only outcomes related to the current hospitalization, across both univariate and multivariate analyses. Int J Occup Med Environ Health. 2025;38(2)