Surgery remains the first choice of cure for early stage lung cancer. However, many patients are diagnosed at advanced stage, and thus miss the opportunity to undergo surgery. As such patients derive limited benefits from chemotherapy or radiotherapy, alternatives focusing on local control have emerged, including iodine-125 seed implantation. The Interstitial Brachytherapy Society, Committee of Minimally Invasive Therapy in Oncology, Chinese Anti-Cancer Association organized a group of multidisciplinary experts to develop guidelines for this treatment modality. These guidelines aim to standardize iodine-125 seed implantation procedures, inclusion criteria, and outcome assessment to prevent and manage procedure-related complications.