In a ten year period 53 patients with hemifacial spasm were submitted to 54 microvascular decompression procedures in the posterior fossa. The technique was the same developed by Jannetta and the initial surgical results were considered excellent in 91% of the cases. The follow-up ranges from 60 days to 7 years, with 40 patients followed for more than two years and 16 for more than five years. Only one patient presented late recurrence of the spasms. There was no death nor serious complications which were usually transient and related do the seventh and eight nerve. In four patients we found no compression of the nerve root. We concluded that no matter what the causes of hemifacial spasm or the mechanisms of action of the surgery are the results of microvascular decompression are excellent and superior to all other clinical and surgical methods of treatment.