Our study demonstrates that PBL (1) mitochondrial COX3 NS variants are associated with risk (being more common in the IPF patients than the control group) and prognosis (being more common in the succumbed than the surviving patients) of IPF; and (2) mitochondrial tRNA variants located in the AC stem, AC loop, variable loop, T-arm, and T loop of the tRNA clover-leaf structure are associated with the risk, and the presence of tRNA variants is associated with poor prognosis of IPF. The gene discussed is MT-CO3; the disease is idiopathic pulmonary fibrosis.