BACKGROUND: Elevated high-sensitivity troponin (hsTnT) after noncardiac surgery is associated with higher mortality, but the temporal relationship between early elevated troponin and the later development of noncardiac morbidity remains unclear. METHODS: Prospective observational study of patients aged ≥45 yr undergoing major noncardiac surgery at four UK hospitals (two masked to hsTnT). The exposure of interest was early elevated troponin, as defined by hsTnT >99th centile (≥15 ng L(−1)) within 24 h after surgery. The primary outcome was morbidity 72 h after surgery, defined by the Postoperative Morbidity Survey (POMS). Secondary outcomes were time to become morbidity-free and Clavien–Dindo ≥grade 3 complications. RESULTS: Early elevated troponin (median 21 ng L(−1) [16–32]) occurred in 992 of 4335 (22.9%) patients undergoing elective noncardiac surgery (mean [standard deviation, sd] age, 65 [11] yr; 2385 [54.9%] male). Noncardiac morbidity was more frequent in 494/992 (49.8%) patients with early elevated troponin compared with 1127/3343 (33.7%) patients with hsTnT