Cardiorenal anemia syndrome has recently been receiving greater attention; however, data regarding the relationship between chronic kidney disease (CKD)/anemia on presentation and in-hospital outcome in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) are still limited in Japan.A total of 1,447 primary PCI-treated AMI patients were classified into 4 groups according to the presence of CKD and/or anemia on hospital admission (with CKD/with anemia n = 222, with CKD/without anemia n = 299, without CKD/with anemia n = 151, without CKD/without anemia n = 775). Angiographic acute results of primary PCI were similar among the 4 groups. The patients with CKD had a significantly higher in-hospital overall mortality rate than the patients without CKD, and in the presence or absence of CKD, patients with anemia tended to have a higher in-hospital mortality rate than the patients without anemia. According to a multivariate analysis, anemia on admission was found to be an independent predictor of in-hospital mortality, whereas admission CKD and admission eGFR were statistically not independent predictors. Moreover, the multivariable adjusted odds ratio of in-hospital death in AMI patients with CKD alone was 1.855 (95% CI 0.929-3.706), and that in AMI patients with CKD/with anemia was 3.384 (95% CI 1.697-6.748).These results suggest that among real-world, unselected Japanese AMI patients undergoing primary PCI, the combination of CKD and anemia on admission confers significant adverse effects on in-hospital mortality.