The purpose of this study was to determine factors that extend the length of hospital stay in patients with ischemic stroke in acute hospital. Clinical data of 462 consecutive patients with acute ischemic stroke were retrospectively researched. These subjects were divided into two groups; short stay group (length of hospital stay < or = 14 days, 238 patients) and long stay group (length of hospital stay > 14 days, 224 patients). Using multivariate statistical methods, the independent factors associated with prolonged hospital stay were investigated. Independent and significant factors associated with prolonged hospital stay were National Institutes of Health Stroke Scale score on admission (OR, 1.072: 95% CI, 1.021 to 1.125), transient ischemic attack (OR, 0.142: 95% CI, 0.021 to 0.966), any complications during hospital stay (OR, 7.975: 95% CI, 3.539 to 17.971) and interval between offer to discharge (OR, 1.441: 95% CI, 1.294 to 1.605). It was suggested that control of complication could decrease length of hospital stay in patients with ischemic stroke in acute hospitals.