Background: The increasing overall survival in cancer patients, due to advances in diagnostics and treatments, lead to an expected increase in diagnoses of brain metastasis (BM). A relevant feature in care-management of this special population is the safety in anticoagulant therapies administration, since cancer-associated thrombosis (CAT) is a concrete complication in patients with BM. In BM patients the risk of developing AEs increase with local treatments (i.e. radiation), and bleeding is a critical issue. Hence, understanding the risk/benefit ratio of anticoagulants in BM is mandatory. We conduct an observational, retrospective study collecting data from patients with BM diagnosis who underwent anti-cancer treatment and had at least a 3 months follow-up. We collect clinical characteristics, treatment, outcome, AEs concomitant medication with a focus on anticoagulants. Finally we assess the correlations between cardiovascular risk factors and increasing bleeding risk with anticoagulants. Methods: The study is observational, retrospective and single center. We included 148 patients with radiological evidence of BM who have at least 3 months follow-up after BM diagnosis. Patients were in charge of Medical Oncology Unit in Careggi University Hospital between 2015 and 2022. Data were collected from medical records. Results: We collected data from 148 patients with BM. Primary cancers were NSCLC (66%; n=98), breast (11%) and melanoma (6%) among the most common. Of the patients described, 87% (n=129) had an ECOG PS 0-1 and clinical condition was complicated by comorbidities as per hypertension (45%), COPD (15%) and diabetes (13%). Radiation was the most locoregional treatments performed (78%; n=115). Patients undergoing systemic treatments, had chemotherapy (51%), immunotherapy (24%) and TKIs (12%) after diagnosis of BM, and a DCR of 75% was achieved. 34% of patients with BM in NSCLC received anticoagulants therapy (n=33). Patients underwent LMWH (n=18) and fondaparinux (n=12), while NAOs were less common (n=5). The treatment goal was VTE prophylaxis, treatment of VTE or PTE respectively in 24% of patients; in 21% of patients anticoagulants were administered as prevention of AF complications. Regarding AEs, there were only one episode of minor hemorrhage (associated with NAO). Although statistical significance was not reached, we highlight a trend between VTE and hypertension in NSCLC population (p=0.069) and between VTE and smoking history (p=0.056) in the total population with BM. Conclusions: The use and safety of anticoagulant treatments in patients with BM have recently gained considerable importance. Our data do not allow us to draw conclusions about the safety of using NAOs or LMWHs in a population with BM. The retrospective nature and smallness of our sample suggest the need for further population studies with larger samples.