Abstract Background and Aims There is increasing evidence about the alloreactivity of natural killer (NK) cells after kidney transplantation. The inhibition and activation cycles of the NK cells are mainly regulated by killer cell immunoglobulin-like receptors (KIRs) which may have extensive allelic polymorphisms within the population. In this study, we examined KIR genes/genotypes in kidney transplant recipients and healthy subjects. We aimed to determine if there are relations between certain KIR genes and graft function in kidney transplant patients. Method Renal transplant patients (n=131) and healthy controls (n=183) from the same ethnic background with similar demographics were included. Transplant patients with an obvious cause of graft dysfunction and presensitized patients were excluded. Recruited patients were classified as graft dysfunction (GD) (n=38) or functioning graft (FG) (n=93) on the basis of allograft rejection and dysfunction. Isolated DNA of all participants were typed for 16 KIR genes with specific primers using PCR. Patient groups were compared for KIR genes/genotypes and clinical features. Results Significant differences were observed for KIR2DL3 and KIR3DL1 genes that were presented with higher frequencies in healthy controls than in kidney transplant recipients (p=0.001 & p=0.006). Comparison between GD and FG groups revealed a protective association for the inhibitor gene KIR2DL1 (p=0.003, OR=0.148). Distribution of the remaining 15 KIR genes and the rates of KIR genotype patterns were not different among these patient groups. Conclusion KIR2DL3 and KIR3DL1 genes were more common in healthy subjects. KIR2DL1 gene was significantly more frequent in patients with FG. We suggest that the presence of KIR2DL1, which is an inhibitor gene for NK cell functions, might be associated with favorable graft function in kidney transplant recipients.