Background: Adult medulloblastoma (AM) is a rare disease and represents 1 % of CNS tumors with an incidence of 0.6 per million per year. Usually arise in the cerebellar hemisphere or dorsal brainsteam. Four molecular subgroups are widely recognized and SHH subgroup are common in AM. Treatment options are usually extrapolated from pediatrics experience, and involve surgical resection followed by radiotherapy +/- chemotherapy. Methods: We conducted a retrospective cohort study in patients with medulloblastoma aged ≥18 years at a tertiary institution in Mexico City. We aim to describe clinical and treatment patterns predicting OS and PFS in an adult cohort of medulloblastomas. Kaplan Meier and Log-rank methods were used for survival analysis. Cox proportional hazard model was used for multivariate analysis. Results: Between 2010 and 2022, 78 patients met the criteria for this study. The median age was 28 years (range 18-62) and 64.1% were men. A total of 75.6% had ECOG 0-1. The desmoplastic was the most frequent histologic variant (35.9%). Surgical resection was performed in 93.6% with R0 resection in 49.3% (n=36), while 76.9% (n=61) underwent ventriculoperitoneal shunt (VPS). A total of 70 pts (89.7%) received adjuvant radiotherapy (RT), and the median time to initiation was 18 weeks. Adjuvant and concurrent chemotherapy were received in 53.8% and 12.8%, respectively. One-third of patients did not receive chemotherapy. Vincristine, cisplatin, and cyclophosphamide was the most common combination chemotherapy regimen (28.5%). PFS and OS in the entire cohort were 27.9 months (mo) (95% CI 9.9-45.9) and 124.3 mo (95% CI 52.8-59.8), respectively. OS in patients with ECOG 0-1 was better with 144.8 mo compared with 51.5 mo for ECOG 2-3 (p<0.001). Patients receiving adjuvant RT survived significantly longer (124.3 mo) than patients without radiation (18.8 mo). Other factors associated with survival were time to RT initiation ≤18 weeks vs >18 weeks (not reached vs 59.1 mo, p=0.018) and VPS insertion (144.8 mo vs 46.5 mo, p=0.023). Multivariate analysis identified performance status such as ECOG 2-3 (HR 2.93; 95% CI 1.3-6.6, p=0.009) and VPS (HR 0.39; 95% CI 0.16-0.93, p=0.034) as independent prognostic factors for OS. Conclusions: in this large cohort of Adult Medulloblastoma, we identified ventriculoperitoneal shunt and performance status as the most important factors related with better survival outcomes.