Pilomyxoid astrocytoma (PMA) is a newly recognized variant of a pilocytic astrocytoma. This report describes a case of a pilomyxoid astrocytoma that occurred in the opticohypothalamus. The patient was a 18-year-old girl who complained decreased visual acuity and visual field over a period of two years. Magnetic resonance imaging (MRI) showed an irregular lobulated tumor with heterogeneous enhancement at the suprasellar region involving the hypothalamus. The mass was partially removed via the subfrontal approach. Its pathology was confirmed to be PMA. Adjuvant chemotherapy with cisplatin and vincristine was started following tumor resection. After four cycles, the mass showed a partial response to the chemotherapy. Although long-term outcome is yet to be determined, the administration of combined cisplatin and vincristine treatment seems to be an effective regimen for a pilomyxoid astrocytoma.