It has been estimated that about 75% of patients diagnosed with multiple sclerosis (MS) have tremor which can be exceedingly disabling. The most common tremor observed in patients with MS is a cerebellar intention tremor ('kinetic tremor') although postural tremor ('static tremor') is also common and often extremely incapacitating. Currently there is no effective medical treatment for the tremor of MS which, in some severe cases, may be abolished by stereotactic thalamotomy. It was reported recently that extracranial application of brief AC pulsed electromagnetic fields (EMFs) in the picotesla (pT) range produced improvement in motor and cognitive functions in patients with MS. The present communication concerns three MS patients with a chronic progressive course of the disease (mean age: 39.3 +/- 8.3 years; mean duration of illness: 11.3 +/- 3.2 years) in whom brief external applications of pulsed EMFs of 7.5 pT intensity reduced intention and postural tremors resulting in significant functional improvement. The report suggests that these extremely low intensity EMFs are beneficial also in the treatment of tremors in MS and that this treatment may serve as an alternative method to stereotactic thalamotomy in the management of tremor in MS. The mechanisms by which EMFs attenuate the tremors of MS are complex and are thought to involve augmentation of GABA and serotonin (5-HT) neurotransmission in the cerebellum and its outflow tracts.