Pulmonary arterial involvement (PAI) is one of the most common causes of mortality in Behçet's disease (BD). In this study, we aimed to evaluate the clinical features, course, and recurrence risk factors of BD-associated PAI. BD patients who were followed up in Marmara University BD outpatient clinic between 1990 and 2023 were included. All data were acquired from the medical records of the patients. PAIs were classified according to the type of the vascular involvement as thrombosis or aneurysm. Factors affecting the risk of relapses were determined using multivariate Cox regression analysis. Among 1350 BD patients, 110 (8.1%) had PAI. The mean age (SD) of patients with PAI was 42.4 (11.6) years, and the male/female ratio was 2.2 (76/34). Thirty-two (29.1%) of 110 patients were asymptomatic. Asymptomatic patients with PAI were significantly younger (p = 0.031) than the symptomatic group. Also, a greater prevalence of females (p = 0.001) and higher recurrence rates (p = 0.019) were observed in the symptomatic group. Pulmonary arterial thrombosis was seen in 104 (94.5%) and aneurysms in 9 patients (6.6%). At least one PAI relapse was observed in 31 patients (28.2%). In multivariate analysis, the Cox regression model was significant (p = 0.013), and not starting anticoagulants independently increased the PAI relapse risk (hazards ratio, 4.36; 95% confidence interval, 1.14-24.1; p = 0.042). Pulmonary arterial thrombosis is the main presentation type of PAI in BD, whereas aneurysmatic formation is rare. Despite immunosuppressive treatment, relapses occur during follow-up in one third of patients with PAI. When anticoagulant therapy is added to immunosuppressive therapy, the relapse rate in BD patients with PAI is significantly reduced.