Recently, there has been increasing interest in treating intraocular retinoblastoma with systemic chemotherapy combined with focal laser therapy and cryotherapy instead of radiotherapy. We developed a system of selective ophthalmic arterial infusion (SOAI) therapy, administering melphalan, the agent which had the greatest effect on retinoblastoma in a clonogenic assay. The SOAI system consists of a combination of a micro-balloon, a guiding catheter, and a flushing hub. After selective catheterization to the cervical segment of the internal carotid artery by the guiding catheter, the micro-balloon was propelled to the portion just distal to the orifice of the ophthalmic artery. During temporary occlusion of the internal carotid artery, melphalan was infused from the introduced catheter tip. We treated 187 patients with intraocular retinoblastoma with SOAI; 563 SOAIs were performed for 610 eyes. The technical success rate was 97.51%. Fourteen examinations failed. No significant complication due to catheterization (including brain infarction) was detected. SOAI, using the balloon occlusion technique, is safe, and its use will prevent the side effects that occur with systemic chemotherapy, and eliminate the need for irradiation and enucleation.