||Recently, advances in novel immunotherapies and molecularly-targeted agents have raised interest in the field of in vitro cancer mimetic platform. Here, we developed a novel 3D vascularized lung cancer-on-a-chip using lung decellularized ECM, which can mimic microenvironment of a natural lung, and collagen hydrogel mixture. Specifically, a spheroid composed of A549 cells for simulating lung cancer, or solid tumor, was encapsulated in the ldECM/collagen hydrogel with lung fibroblasts (HLFs) and endothelial cells (HUVECs). In addition, two channels were fabricated in the hydrogel construct, to bio-mimick perfusable vessel structures which resemble artery and vein. In our proposed 3D vascularized lung cancer-on-a-chip, we were able to confirm the potential of simulating metastasis.