A case of a huge cervical neurofibroma associated with von Recklinghausen's disease is reported. The patient with von Recklinghausen's disease was a 48-year-old woman complaining of a rapidly growing mass around the neck for the last 6 months. In von Recklinghausen's disease, which corresponds to neurofibromatosis-I, gigantic tumors around the neck often occur. The present case was classified as a plexiform neurofibroma which is derived from the peripheral nervous system, and this type frequently shows malignant change in contrast to other types of neurofibroma. In general, it is difficult to determine the origin of the nerve in cervical neurofibromas. A total extirpation of the tumor was done in our case, and revealed the nerve of origin to be the vagal nerve. Pathologically, H-E stained specimens showed that the tumor was a benign neurofibroma. However, immunostaining of the majority of the tumor cells were positive for PCNA. These results suggest that the tumor of our case possessed a low malignant potential. To date, neither local recurrence nor distant metastasis has been found on subsequent examinations.