Heart failure (HF) increases the risk of ischemic stroke. Data regarding the incidence and predictors of ischemic stroke during hospitalization for HF are limited. The study population of this retrospective cohort study consisted of patients with congestive HF, consecutively admitted to our center from October 2010 to April 2014. We excluded patients complicated with acute myocardial infarction, infective endocarditis, and takotsubo cardiomyopathy. We also excluded those with dialysis or mechanical circulatory support. We investigated the incidence of ischemic stroke during hospitalization for HF. Thereafter, we divided the patients without oral anticoagulants at admission into two groups: patients with ischemic stroke and those without it, and explored the predictors of ischemic stroke. A total of 558 patients (287 without atrial fibrillation (AF), 271 with AF) were enrolled. The mean age was 76.8 ± 12.3 years, and 244 patients (44 %) were female. The mean left-ventricular ejection fraction was 47.4 %. Oral anticoagulants were prescribed in 147 patients (8 without AF, 139 with AF). During hospitalization (median length 18 days), symptomatic ischemic stroke (excluding catheter-related) occurred in 15 patients (2.7 % of the total, 8 without AF, 7 with AF). Predictors significantly associated with increased risk of ischemic stroke in patients without oral anticoagulants were as follows; short-term increases in blood urea nitrogen after admission (at day 3; odds ratio (per 1 md/dl): 1.06, 95 % confidence interval (CI) 1.01–1.11, p = 0.02, and at day 7; odds ratio: 1.03, 95 % CI 1.00–1.07, p = 0.03, respectively), and previous stroke (odds ratio; 3.33, 95 % CI 1.01–11.00, p = 0.04). The incidence of ischemic stroke during hospitalization for HF was high, even in patients without AF. Previous stroke and short-term increases in blood urea nitrogen was significantly associated with the incidence of ischemic stroke.