Objectives Choline has been identified as a promising marker of coronary inflammation, plaque destabilisation and ischaemia. We sought to evaluate plasma choline levels for rapid confirmation or exclusion of acute myocardial infarction (AMI) in the Emergency Department (ED) and for predicting major adverse cardiac events (MACE). Methods We prospectively recruited 361 patients who presented to the ED with suspected cardiac chest pain within the previous 24 h. Blood was drawn at the time of presentation for plasma choline levels. All patients underwent troponin T testing ≥ 12 h after symptom onset and were followed up for the occurrence of MACE within 6 months. Whole blood choline (WBCho) levels were also measured in a convenience sample of 39 patients. Results Plasma choline levels did not help to predict a diagnosis of AMI (odds ratio (OR) 1.00 (95% confidence intervals (CI) 0.91–1.10, p = 0.98). For a diagnosis of AMI the area under the receiver operating characteristic (ROC) curve was 0.48. Plasma choline was not predictive of the combined endpoint of MACE (OR 1.03, 95% CI 0.95–1.12, p = 0.45) but predicted AMI within 6 months (OR 1.31, 95% CI 1.09–1.56, p = 0.003). WBCho levels were significantly different to plasma levels and were predictive of MACE. Conclusions Plasma choline, measured at the time of ED presentation, is not a diagnostic marker of AMI but predicts AMI within 6 months. While plasma choline failed to predict MACE, WBCho was predictive and warrants further evaluation.