Microvascular decompression (MVD) is an effective and safe treatment option that offers the prospect of definitive cure for hemifacial spasm (HFS). However, there are potential risks of complications for MVD associated with retromastoid suboccipital craniectomy (RmSOC) and cranial nerves in particular. The purpose of this study was to identify clinical characteristics of possible complications after MVD for HFS and to establish appropriate management concept of these complications. We retrospectively reviewed medical records of 2040 patients who underwent RmSOC with MVD for HFS at Samsung medical center between January 1998 and March 2013. Of 2040 patients, 2027 were followed (99.4 %). Of the 2027 patients, 1841 (90.8 %) exhibited complete relief or minimal symptoms, and 113 (5.6 %) reported improved spasm but had mild remnant symptoms. After operation, the most frequently developed complications were facial nerve palsy (8.19 %), followed by middle ear effusion (4.90 %) and hearing loss (3.63 %). There were two cases of supratentorial subdural hemorrhage, three cases of infarction. MVD was found to be safe and effective treatment for HFS, in consistent with previous reports. Some of the complications such as facial nerve palsy, middle ear effusion, and hearing loss are relatively common. However, they have mild clinical courses that are usually transient.