Given that mitochondria are the source of ROSproduction in cells, the aim of this study was to scan nine mitochondrial genes (MT-COX2,MT-tRNALys , MT-ATP8, MT-ATP6, MT-COX3, MT-tRNAGly , MT-ND3, MT-tRNAArg and MT-ND4L) for mutations in infertile patients with varicocele. The gene discussed is MT-ND4L; the disease is Infertility.