Background:  Prolonged air leak (PAL) is a significant complication following thoracic surgery, leading to increased morbidity and prolonged hospital stays. Objective: This study aimed to investigate the predictors of prolonged air leak PAL following thoracic surgery. Patients and Methods: This prospective clinical study enrolled 42 patients who underwent thoracic surgery. They were divided into a PAL group (n=5) and a non-PAL group (n=37). Data collection included patient demographics, surgical details, and postoperative outcomes. PAL was defined as an air leak lasting more than 4 days. Statistical analysis was performed to compare variables between PAL and non-PAL groups. Results: Obesity (P = 0.002), diabetes mellitus (P = 0.005), chronic obstructive pulmonary disease (P < 0.001), low vital capacity (P < 0.001), low forced vital capacity (P < 0.001), low diffusing lung capacity (P < 0.001), steroid use (P < 0.001), and emphysematous lung (P < 0.001) were significantly associated with PAL. Pleural adhesion (P < 0.001), location of lobectomy (P = 0.026), and operative time (P < 0.001) were also significantly associated with PAL. However, smoking status, cardiovascular disease, previous chest surgery, lobectomy, and number and size of chest tubes, did not significantly correlate with PAL. The duration of hospital stay was significantly prolonged in the PAL group (P < 0.001). Conclusion: Our study identified several factors associated with PAL following thoracic surgery. These findings contribute to our understanding of PAL risk factors and can guide preventive strategies to improve patient outcomes after thoracic surgery.