Drug-coated balloon (DCB) is a potential treatment for patients with low restenosis risk in vertebral artery origin stenosis (VAOS). However, the clinical data of long-term outcome are limited. To evaluate the safety and efficacy of a DCB in patients with severe VAOS. A prospective, non-randomized, single-center pilot study enrolled 30 patients with severe VAOS treated with DCB between 2017 and 2018. The first 20 patients were treated with a balloon-to-vessel ratio of predilation (pBVR)＜0.8 (small-size balloon predilation) and the following 10 patients were treated with a pBVR 0.8-1.0 (large-size balloon predilation). Primary safety endpoints included 30-day death, stroke, and transient ischemic attack (TIA). The main efficacy outcome was restenosis at 6 months, defined as a peak systolic velocity >140 cm/s measured by Doppler ultrasound. Long-term outcomes, including TIAs, stroke, death, and modified Rankin Scale score, were followed up to 2 years. Technical success (<50% residual stenosis) was achieved in 26 patients (mean age 66.2±7.0; seven women). Four patients received bailout stenting and were excluded. Ultrasound confirmed restenosis at 6 months in 10 (38.5%) of 26, which was significantly less frequent in LSBP (LSBP vs SSBP=10% vs 56.3%, p<0.05). No adverse events occurred within 30 days of treatment. 19 patients were followed up for 2 years, with two deaths due to cancer. This pilot study suggests that DCB is a safe approach for VAOS. The relatively low restenosis rate indicates the its potential long-term efficacy for VAOS. Future randomized controlled trials to confirm its efficacy are warranted. © Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.