The association between multiple sclerosis and tumours of the central nervous system is unusual. The authors analyzed the clinico-pathological elements of the correlation. The pertinent literature on this subject is critically reviewed. Ten cases of patients with an history of multiple sclerosis for more than 15 years and a clinical and radiological evidence of brain tumour were submitted to surgery in order to remove the lesion and/or to chemo- and radiotherapy. The various aspects of the association were studied in detail. A patient with multiple sclerosis, particularly with atypical symptoms, should be evaluated by an annual MRI investigation with intravenous paramagnetic contrast medium. The diagnostic work-up should be: clinical and radiological assessment; MRI in the event of atypical symptoms; Sstereotactic or neuronavigation-aided biopsy in any suspected lesions. Patients with multiple sclerosis and glioma present survival times identical to those observed in patients not suffering from multiple sclerosis. The coexistence of multiple sclerosis and brain tumours does not seem to influence the clinical evolution of either of these pathologies. We believe that it is important to achieve an early diagnosis of brain tumour in such patients with a clinical and neuroradiological follow up, so that they can be treated promptly.