Through measuring the mRNA levels of immune (A2M, TLR2, TGF-β, IRAK3, CCl2, FCAMR, and iNOS), metabolic (ADAMTS20, KCNT2, MAP3K4, MAPK14, RXFP1, FKBP5, RXFP1, and EPHA4), and antioxidant (SOD3, CAT, GPX, and NDUFS5) genes, we examined the changes in the immune, metabolic, and antioxidant state in postparturient endometritis-affected buffalo cows compared with healthy ones. The gene discussed is NOS2; the disease is endometritis.