Contrast-induced nephropathy (CIN) is a complex syndrome of acute kidney injury induced by exposure to intravascular contrast media. CIN occurs frequently in patients undergoing urgent percutaneous coronary intervention (PCI) and is associated with poor outcomes, making it a major challenge faced by interventional cardiologists. It has been suggested that female sex is a risk factor for development of CIN following PCI. However, no data exist in the literature concerning the risks of postmenopausal women with acute myocardial infarction (AMI) developing CIN after undergoing urgent PCI. To explore the incidence, risk factors and in-hospital outcomes of CIN in this special population, we analyzed 69 postmenopausal women with AMI treated with urgent PCI. CIN was defined as a relative increase of >25% or an absolute increase of >or=0.5 mg/dL in serum creatinine concentration from the baseline value 72 h after exposure to contrast medium. We found 1) the incidence of CIN was 37.68%; 2) patients with CIN had worse in-hospital outcomes, including longer hospital stay and more in-hospital adverse events; and 3) in multivariate logistic analysis, independent risk factors for CIN included a longer menopausal duration and the implantation of an intra-aortic balloon pump (an indirect indicator of hemodynamic instability). These results indicate that CIN is a frequent complication associated with worse in-hospital outcomes in postmenopausal women with AMI who are undergoing urgent PCI, particularly those with longer menopausal duration and hemodynamic instability. It is therefore necessary to pay more attention to preventive strategies for renal protection in this special population.