Background We aimed to investigate the predictive value of the fibrinogen-to-albumin ratio (FAR) regarding the development of major cardiovascular events (MACE) in patients treated with percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Methods This was a prospective, observational cohort study that included 261 consecutive patients who were treated with PCI. The patients were grouped according to the occurrence of MACE during the follow-up period. Results During follow-up, MACE occurred in 68 (26%) patients. The FAR was independently predictive of MACE (HR: 1.017, 95% CI: 1.010-1.024, p < 0.001). In addition, left ventricular ejection fraction (LVEF) and a diagnosis of ST-segment elevation myocardial infarction (STEMI) were independent predictors of MACE. The area under the curve (AUC) of the multivariable model, including LVEF and diagnosis of STEMI, was 0.707 (95% CI: 0.631-0.782, p < 0.001). When the FAR was added to the multivariable model, the AUC was 0.770 (95% CI: 0.702-0.838, z = 2.820, difference p = 0.0048). Conclusion The FAR could be used for the prediction of MACE in patients with ACS who have undergone PCI.