Thirty malignant schwannomas from an 18-year period were studied, and the patients were divided into 3 groups: one with Recklinghausen's disease, one with tumours related to nerves but without Recklinghausen's disease and finally one with a histopathology best compatible with malignant schwannoma. On all tumours a histopathological grading was performed, and all except two were found to be high-grade malignant. The follow-up is from 2 to 20 years, and only two of the living patients have not yet been followed for 5 years. One patient has been lost during the follow-up period. In the remaining 27 patients the 5-year survival is 48%. The factors essential to the prognosis are: the tumour localization, size, grade of malignancy and radical surgical treatment. The coexistence of Recklinghausen's disease and malignant schwannoma seems not in itself to give a worse prognosis; it is rather the large tumours and unfavourable localizations in this group of patients that shortens the survival, the 5-year survival being 37.5%.