eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2022-09-29 15 3 1791 1795 10.13005/bpj/2518 45652 article I Wayan Niryana 1 Steven Awyono 2 Kevin Kristian Putra 2 Nyoman Golden 1 Neurosurgery Division, Department of Surgery, Faculty of Medicine, Universitas Udayana, Sanglah General Hospital, Bali, Indonesia Neurosurgery Residency Program, Faculty of Medicine, Universitas Udayana, Sanglah General Hospital, Bali, Indonesia Dandy-Walker Malformation presents  as a congenital anomaly that affects the posterior fossa. Presenting hydrocephalus as secondary to Dandy-Walker Malformation is the main concern and complication. The cyst formation in the posterior fossa obstructs the cerebrospinal flow that led to the hydrocephalus. Ideal management to treat Dandy-Walker malformation are varied. Shunting, cyst excision, and endoscopy third ventriculostomy are the proposed management. Case Report Presenting a case of a 1-month-age male baby who was diagnosed with vermis agenesis and posterior fossa enlargement by antenatal ultrasound. Later on, Magnetic Resonance Imaging revealed Dandy-Walker Malformation with hydrocephalus and aqueduct obstruction. Cystoperitoneal shunt was performed for this patient. Proximal shunt trajectory measured from Magnetic Resonance Imaging. As the goal of therapy is to achieve normal development, this patient needs long-term follow-up in collaboration with pediatric and physiotherapy. After 18 months of follow-up, he was able to crawl with routine and proper physiotherapy. Conclusion Hydrocephalus in Dandy-Walker Malformation patients related to aqueduct obstruction may be treated with a single Cystoperitoneal shunt. Aqueduct obstruction in these patients may be temporary due to high pressure on the posterior fossa that pushed the vermis forward. Cystoperitoneal shunt may reduce posterior fossa pressure and then deprive the pressure that obstructs aqueduct. https://biomedpharmajournal.org/vol15no3/cystoperitoneal-shunting-for-patient-with-hydrocephalus-associated-with-aqueductal-obstruction-in-dandy-walker-malformation-a-case-report/ Aqueduct Obstruction  Cystoperitoneal shunt  Dandy-Walker malformation  Hydrocephalus  Posterior Fossa Cyst Formation