This study is try to explore if the mitochondrial DNA 889bp and 3895bp deletions in human lymphoblastoid cell line could be induced by ionizing radiation. Human normal lymphoblastoid cell line samples were exposed to 10Gy ,60,Co γ-rays ,in vitro, and pure mitochondrial DNA were extracted at 24h and 48h after irradiation respectively. A nest-PCR method was used to analyze the 889bp or 3895bp deletions before and after exposure. The final PCR products were purified, sequenced and BLASTed on standard human mitochondrial genome sequence database. The results showed that the 889bp and 3895bp deletion were not detected for the cell line samples not exposed to ,60,Co γ-rays. The 889bp and 3895bp deletions were detected on samples exposed to 10Gy ,60,Co γ-rays, either at 24h or 48h after irradiation respectively. The BLAST results showed that the 889bp and 3895 deletions flanked 11688bp-12576bp, 548bp-4443bp with the piece of AAGCTTCA ,&, CCCATACCCCGAA, respectively. These observations suggested that the 889bp and 3895bp deletion could be induced by ionizing radiation on lymphoblastoid cell lines samples.