Background Thrombolysis in Myocardial Infarction (TIMI) flow grading is limited by subjectivity and imprecision. The corrected TIMI frame count (cTFC) has been proposed to obviate these problems. We sought to validate the utility of the cTFC in predicting adverse clinical outcomes after reperfusion therapy. Methods and Results We used angiographic core laboratory data from the Intravenous nPA for Treating Infarcting Myocardium Early Study (lanoteplase versus alteplase) to assess the predictive capacity of both final TIMI flow and cTFC on 30 day-composite adverse outcome (death, reinfarction, and new or worsening congestive heart failure). Only 390 angiograms of 586 were analyzable for cTFC; 33.4% of angiograms could not be analyzed for cTFC because filling of distal landmarks was not visualized for technical reasons such as inadequate panning. The interobserver correlation for determination of the cTFC was 0.99 and the intraobserver correlation was 0.97. The cTFC in the group with adverse outcomes was 49 ± 34; in the group without adverse outcomes, it was 44 ± 31 (P = .27). Of note, the TIMI flow correlated with adverse outcome in the overall group of patients (P = .018, area under the receiver-operator characteristic curve [c] = 0.590) as well as in the group of patients with cines analyzable for cTFC (P = .025, c = 0.600). The independent correlates of adverse outcomes were age (P < .001), heart rate (P = .001), TIMI flow grade (P = .027), and infarct location (P = .038) but not cTFC. Conclusions The cTFC did not predict adverse outcomes in this population of patients but did show excellent reproducibility within our core laboratory. (Am Heart J 1999;138:785-90.)