Yolk sac tumors (endodermal sinus tumors) are malignant germ cell tumors in which neoplastic germ cells differentiate into extraembryonic structure and may contain cysts resembling yolk sac vesicle. These rare neoplasms usually arise in the ovary and testis, although they have been discovered insuch midline extragonadal sites as the retroperitoneum, anterior mediastinum, sacrococcygeal area, parapineal region. However, we are unaware of any previous cases of this neoplasm arising in the nasal cavity. Serum α-fetoprotein is the useful tumor marker and it is considered as clinical monitor of tumor recurrence. A 3-year-old girl with yolk sac tumor of the nasal cavity was encountered. The serum α-fetoprotein was elevated to 948ng/mL before operation. One month after medial maxillectomy, the residual tumor grew rapidly and serum α-fetoprotein elevated to 19,480ng/mL. Chemotherapy regimens with bleomysic, etoposide and cisplatin were given, then the serum α-fetoprotein returned to normal level. There is no evidence of tumor recurrence in 1 year follow-up.