In order to observe the change of the clinical results after Microvascular Decompression(MVD), we followed up 261 cases with hemifacial spasm(HFS). The patients were operated between Nov. 1985 and Aug. 1994. The length of observation had been more than 6 months in all cases. The mean age of the patients was 47.0 years old and the mean duration of symptom was 8.2 years. Female constitutes 82.8% of the total an right side was involved in 52.1%. The most common offender was the anterior inferior cerebellar artery (51.0%), and 33% involved multiple vessels. The most common offender was the anterior inferior cerebellar artery (51.0%), and 33% involved multiple vessels. The postoperative complications occurred in 84 cases, 4 of which were permanent. However, there were no mortalities. Among the 226 cases, which were followed up for more than 6 months after the MVD, the final clinical results of 187 cases were excellent, the success rate was 91.7%, and the patients' satisfaction rate was 96.1%. The rate of excellence was 61.1% at POD 7th and 82.7% at final, respectively. The delayed resolution of the HFS during follow-up comprised 37.4% of the completely resolved cases. According to the above results, the clinical status of HFS after MVD continuously changes, therefore follow-up observation after MVD is needed to evaluate the operative results, especially in the delayed resolved cases.