Brain magnetic resonance imaging (MRI), multimodality evoked potentials (EPs) and cerebrospinal fluid examination were performed in 42 patients with myelopathy of undetermined aetiology in order to detect abnormalities usually related to multiple sclerosis (MS). Patients were divided into three groups: insidious-onset myelopathy with only motor signs (group A; 11 patients), with both motor and sensory signs (group B; 18 patients) and acute-onset myelopathy (group C; 13 patients). Multiple brain MRI lesions were found in 18 patients (2 of group A, 13 of group B and 3 of group C). Another 7 patients had a single white-matter lesion. Visual EPs were abnormal in 21 and brain-stem auditory EPs in 12 patients. Paraclinical tests supported the diagnosis of MS in 25 patients (60%) by showing subclinical brain abnormalities. Oligoclonal bands were found in 16 of these 25 patients. The findings strongly suggest a diagnosis of MS in the patients of group B.