Background and Purpose— Cerebral microbleeds (CMBs) are a marker of small vessel diseases, including hypertensive arteriopathy and cerebral amyloid angiopathy, and may be associated with cognitive impairment. The relationship between CMBs and cognitive function in ischemic cerebrovascular disease remains uncertain. We, therefore, investigated the cognitive impact of CMBs in a cohort of patients with ischemic stroke or transient ischemic attack. Methods— All patients underwent detailed and comprehensive neuropsychological testing and standardized MRI, including fluid attenuation inversion recovery, T1, T2, and gradient-recalled echo T2*-weighted sequences. CMBs, white matter changes, lacunes, and territorial cortical infarcts (defined by standardized criteria) were identified, and associations with cognition assessed. Results— Three hundred twenty patients with a diagnosis of ischemic stroke or transient ischemic attack were included. Of these, 72 (22.5%) had at least 1 CMB. Of all the cognitive domains tested, only executive impairment was more prevalent in patients with CMBs than without (38% versus 25%; P =0.039). In univariate analysis, the presence of strictly lobar (but not deep) CMBs was associated with executive impairment (odds ratio, 2.49; 95% confidence interval, 1.16–5.36; P =0.019). In adjusted multivariate analyses, the presence (OR, 2.34; 95% confidence interval, 1.08–5.09; P =0.031) and number (OR, 1.33; 95% confidence interval, 1.04–1.69; P =0.022) of strictly lobar CMBs were significantly associated with executive impairment. CMBs were not associated with impairment in other cognitive domains. Conclusions— Strictly lobar CMBs are independently associated with executive dysfunction in patients with ischemic stroke or transient ischemic attack. Our findings suggest that a microangiopathy related to strictly lobar CMBs (eg, cerebral amyloid angiopathy) contributes to cognitive impairment in this population.