Background: Glioblastoma is the most common primary brain tumour in adulthood, accounting for 70% of all malignant brain tumours in the central nervous system.Gglioblastomas occur more frequently in adulthood (median age 64 years), they can occur at any age and rarely occur in children. Glioblastoma occurs mostly in the fifth or sixth decade of life and is rare at a young age In this case are rare because glioblastoma occurs in young age. Objective: To find out the characteristics of glioblastoma in young age. Patients and Methods: In this case, glioblastoma was found in men aged 17 years and 22 years, with its location in the right frontotemporal lobe and the left frontotemporoparietal lobe—diagnosis of glioblastoma based on imaging and tumour biopsy. Imaging can be done with CT Scan, Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET). The most sensitive and specific examination is MRI. Results: In this case, both biopsies were performed with conclusions on glioblastoma and a CT scan of the head, which provided an overview of masses in the right frontotemporal lobe and left frontotemporoparietal lobe. MRI was only performed in case 2, and there was a mass in the left frontotemporoparietal lobe, mesencephalon, pons, optic chiasm, proximal right-left optic nerve, covering the left internal carotid artery to the subcutaneous left frontotemporoparietal region accompanied by fluid collection with chronic bleeding components, cerebral edema with subalpine herniation. To the right ± 9mm and a downward transtentorial herniation at the mesencephalon level, right lateral ventriculomegaly. The therapies that have been given to both patients are excision, radiotherapy and chemotherapy. Conclusion: Both patients were diagnosed with glioblastoma based on anamnesis, physical examination, supporting examination and definitive diagnosis by histopathological examination. Both cases are extremely rare because epidomological glioblastoma is common at ages 45-65 and very rare in less than 30 years of age. Glioblastoma at a young age can occur due to genetic mutations. The genetic mutation most commonly associated with glioblastoma is the Isocitrate Dehydrogenase 1 (IDH 1) mutation. IDH1 mutation occurred in 82% of cases with secondary glioblastoma. This IDH 1 mutation is often associated with younger age and better prognosis. The IDH 1 mutation must be accompanied by a mutation of TP53 for progression to the tumour. Genetic examination is important to determine the prognosis of patient with glioblastoma