Background To investigate the relationship between anemia and contrast-induced nephropathy (CIN) in patients with cbronic kidney disease (CKD) undergoing percutaneous coronary intervention (PCI) Methods A total of 292 consecutive patients with CKD undergoing PCI were enrolled.Patients were divided into two groups (anemic group,n=101,and non-anemic group,n=191) according to preoperative hemoglobin (Anemia was defined as hemoglobin＜130 g/L in men and＜120 g/L in women).We evaluated the incidence of CIN and other major adverse cardiac events in hospital.The relationship between CIN and anemia was evaluated by multivariate logistic regression analysis.