Background and Purpose— The relationships between different infection types and stroke subtype are not well-characterized. We examined exposure to infections in different organ systems in different time periods before the acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. Methods— We used the New York State Inpatient Databases and Emergency Department Databases (2006–2013). Validated International Classification of Diseases , Ninth Edition definitions identified index hospitalizations for acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, and emergency department visits and hospitalizations for infection (skin, urinary tract infection, septicemia, abdominal, and respiratory). We used case cross-over analysis with conditional logistic regression to estimate odds ratios (OR) for the association between each infection type during case periods compared with control periods 1 year before. Results— Every infection type was associated with an increased likelihood of acute ischemic stroke. The greatest association was for urinary tract infection, with OR of 5.32 (95% CI, 3.69–7.68) within the 7-day window. The magnitude of association between urinary tract infection and intracerebral hemorrhage was of lesser magnitude, with OR of 1.80 (1.04–3.11) in the 14-day exposure period and OR of 1.54 (1.23–1.94) in the 120-day exposure period. Only respiratory infection was associated with subarachnoid hemorrhage, with OR of 3.67 (1.49–9.04) in the 14-day window and 1.95 (1.44–2.64) in the 120-day window. Conclusions— All infection types were associated with subsequent acute ischemic stroke, with the greatest association for urinary tract infection.