A 10-year-old spayed female Abyssinian cat was presented with cluster limbic focal seizures with secondary generalisation. From magnetic resonance imaging (MRI) findings, the cat was diagnosed clinically as having a glioma in the left piriform lobe, and hypofractionated radiation therapy (RT) was performed using a linear accelerator. Although the tumour size had reduced significantly at 4 months after RT, recurrence was observed at 11 months after RT. Additional RT was performed and was effective; however, recurrence was observed at 11 months after the additional RT. Chemotherapy was started using nimustine (ACNU; 30 mg/m(2), every 6 weeks). Tumour regression was confirmed by follow-up MRIs from 2 to 5 months after starting chemotherapy. Four years and 2 months after the first presentation the cat died as a result of tumour lysis syndrome following treatment of a high-grade lymphoma. Histopathological diagnosis of the brain tumour confirmed anaplastic oligodendroglioma.