Background and Purpose— National guidelines recommend lipid testing for all patients with ischemic stroke and transient ischemic attack. This study examined the frequency and predictors for in-hospital low-density lipoprotein testing using data from a nationwide stroke registry. Methods— Between 2003 and 2008, Get With The Guideline–Stroke (GWTG–Stroke) hospitals (n=981) contributed 479 284 consecutive ischemic stroke or transient ischemic attack admissions. Logistic regression models were used to determine patient and hospital characteristics associated with lipid testing. Results— Frequency of LDL measurement increased from 54.3% in 2003 to 81.9% in 2008 ( P <0.001), the adjusted OR for LDL measurement was 1.23 per additional calendar year (95% CI, 1.18 to 1.29; P <0.001). The frequency of LDL measurement also increased with longer hospital program participation; the adjusted OR was 1.17 per additional year of GWTG–Stroke participation (95% CI, 1.12 to 1.23; P <0.001). LDL measurement was lower in women, nonsmokers, those with atrial fibrillation, those with a history of stroke or transient ischemic attack, and in those with transient ischemic attack (versus ischemic stroke; all P <0.001). LDL ≥100 mg/dL was seen in 52.1% of those tested, including in 35.5% of patients already prescribed lipid-lowering therapy before admission. Conclusions— Rates of LDL measurement in hospitalized patients with ischemic stroke and transient ischemic attack have improved dramatically in this large quality improvement program, although disparities in testing still exist. Testing frequently revealed an LDL level that could prompt a change in clinical management.