Objective To investigate the etiology and risk factors for ischemic stroke in young adults.Methods The clinical data of 71 young adult patients with ischemic stroke and 80 middle-aged and elderly patients with ischemic stroke were collected; 140 young adults who underwent physical examination were selected as controls. All data were analyzed to investigate the etiology and risk factors for ischemic stroke in young adults.Results According to the TOAST classification, the young adult patients were classified into five subgroups: large artery atherosclerosis (LAA) (40.8%), small artery occlusion (SAO) (28.2%), stroke of undetermined etiology (UND) (15.5%), stroke of other determined etiology (OTH) (9.9%), and cardioembolism (CE) (5.6%). Compared with the middle-aged and elderly patients, the young adult patients had a significantly higher proportion of UND cases (P<0.05). The risk factors for ischemic stroke in young adults were smoking, hyperlipidemia, hypertension, diabetes, and heart disease. Compared with the middle-aged and elderly patients, the young adult patients had a significantly higher proportion of males (P<0.05).Conclusions LAA is the most common subtype of ischemic stroke in young adults. The development of ischemic stroke in young adults is the consequence of multiple factors.