Pulmonary vein (PV) stenosis has emerged recently as an important issue in patients who received radiofrequency (RF) ablation of atrial fibrillation (AF). Serial pathophysiological responses, including thrombosis, metaplasia, proliferation and neovascularization, may lead to PV stenosis after RF energy application around or inside the PV ostia. The clinical manifestations of PV stenosis consist of chest pain, dyspnea, cough, hemoptysis, recurrent lung infection and pulmonary hypertension. Although PV stenosis can be asymptomatic, its severity may be related to the numbers of stenotic PVs, the degree and chronicity of PV stenosis. The incidence of PV stenosis (defined as luminal diameter reduction >50%) detected by spiral computer tomography scan or three dimensional magnetic resonance angiography was from 0 to 7% per PV after isolation of PVs from left atria. Furthermore, some patients may show late progression of PV stenosis during follow-up. The first choice of treatment for symptomatic PV stenosis is PV angioplasty with stenting; however, restenosis were reported occasionally. Several studies have analyzed the predictors of PV stenosis, and the results are controversial. However, the consensus for prevention of PV stenosis should include less energy application and the ablation site more close to the atrial site.