BACKGROUND AND PURPOSE: No evidence is available on the benefits of preventive suboccipital decompressive craniectomy (SDC) for patients with cerebellar infarction. The purpose of this matched case-control study was to investigate whether preventive SDC was associated with good clinical outcomes in patients with cerebellar infarction and to evaluate its predisposing factors. METHODS: Between March 2007 and September 2015, 28 patients underwent preventive SDC. We performed propensity score matching to establish a proper control group among 721 patients with cerebellar infarction during the same period. Group A (n=28) consists of those who underwent preventive SDC, and group B (n=56) consists of those who did not undergo preventive SDC. We analyzed and compared clinical outcomes between groups. RESULTS: Clinical outcomes were better in group A than in group B at discharge (P=0.048) and 12-month follow-up (P=0.030). Group B had more deaths within 12 months than group A (log-rank, P<0.05). Logistic regression analysis showed that preventive SDC (odds ratio, 4.815: P=0.009) and the absence of brain stem infarction (odds ratio, 2.862: P=0.033) were independently associated with favorable outcomes (modified Rankin Scale score of 0-2) at 12-month follow-up. CONCLUSIONS: Favorable clinical outcomes including overall survival can be expected after preventive SDC in patients with a volume ratio between 0.25 and 0.33 and the absence of brain stem infarction. Among these patients, preventive SDC might be better than the best medical treatment alone.