The operative findings and results of microvascular decompression (MVD) on 310 Chinese patients with hemifacial spasm are analyzed in this report. The operations were performed at the Neurological Institute of the Veterans General Hospital-Taipei between January 1983 and June 1990. The length of follow-up ranged from 6 months to 8 years (mean, 4.3 years); 273 patients (88%) had complete relief of spasm within 3 days after one MVD, and the remaining 37 patients (12%) showed no immediate postoperative improvement. Sixteen (5.2%) of these 37 initially unresponsive patients subsequently experienced complete relief, which occurred from 4 days to 22 months (median, 21 days) after one MVD; 13 others (4.2%) had complete relief immediately after the second MVD; another 3 (1%) had delayed complete relief 6, 9, and 11 months after the second MVD, respectively; and the remaining 5 (1.6%) only had delayed partial relief, which occurred 2 to 9 weeks after one MVD. Late recurrence occurred in three patients (1%). These immediate and long-term results lend support to the conclusion that the timing of reoperation can be postponed for a period of 3 to 4 weeks in the event of an initial failure to get improvement, and that a second MVD may be of value.