Objectives: The effect of acute kidney injury (AKI) on outcomes of transient ischemic attack (TIA) is largely unknown. We wanted to determine the impact of AKI on the outcomes of patients admitted with TIA. Methods: Data from all adult patients admitted to the U.S. hospitals between 2005 and 2011 with a primary discharge diagnosis of TIA and secondary diagnosis of AKI were included, using the nationwide in-patient dataset. The association of AKI with TIA-related mortality and discharge outcomes was analyzed after adjusting for potential confounders using logistic regression analysis. Results: Of the 1,173,340 patients admitted with TIA, 45,974 (3.8%) had AKI. Dialysis was required in 29 (0.06%) patients. TIA patients with AKI had higher rates of moderate-to-severe disability (21.2 vs. 13.7%, p ≤ 0.0001), and in-hospital mortality (0.6 vs. 0.1%, p ≤ 0.0001) compared with those without AKI. After adjusting for age, sex, and potential confounders; TIA patients with AKI had higher odds of moderate-to-severe disability [OR 1.3, 95% CI 1.2-1.4, p < 0.0001] and death (OR 4.2, 95% CI 3.0-6.1, p < 0.0001). Conclusions: AKI in patients with TIA is associated with significantly higher rates of moderate-to-severe disability at discharge and in-hospital mortality compared with those without AKI.