This prospective observational study aims to investigate the frequency and clinical significance of biofilm formation on thoracic chest drains used after thoracic surgery. Biofilms are structured bacterial communities that adhere to surfaces and can promote infection and antibiotic resistance. In this study, small samples from the tips of chest drains will be collected under sterile conditions at the time of drain removal and analyzed in the microbiology laboratory. The main objectives are to evaluate the relationship between the duration of chest drain placement and the presence of biofilm, and to identify the antibiotic resistance profiles of microorganisms isolated from these biofilms. Secondary outcomes include the association between biofilm formation, postoperative infections (such as empyema or wound infection), and the length of hospital stay. This study will be conducted at Ondokuz Mayıs University Faculty of Medicine, Department of Thoracic Surgery, in collaboration with the Department of Microbiology. The findings are expected to contribute to better understanding of optimal drain management and infection prevention strategies after thoracic surgery.