The present communication concerns a 46 year old woman with a 10 year history of chronic progressive multiple sclerosis (MS) in whom external application of magnetic fields (MF) (7.5 picoTesla; 5 Hz) during a period of remission resulted in a rapid and dramatic improvement in symptoms including vision, cerebellar symptomatology (ataxia and dysarthria), mood, sleep, bowel and bladder functions as well as fatigue. Improvement in the patient's symptoms was associated with normalization of the pretreatment latencies of the visual evoked potentials and brainstem auditory evoked potential responses within a week after initiation of magnetic treatment. This report demonstrates that treatment with picoTesla MF is an effective, nonpharmacological modality in the management of MS and for the first time documents reversal of abnormal evoked potential responses by this treatment. The pineal gland is a magnetosensor. As MF affect the release of the pineal gland's principal hormone, melatonin, it is hypothesized that the effects of picoTesla MF in MS are partly mediated by the pineal gland which has recently been implicated in the pathogenesis of MS (Sandyk, 1992 a; b).