||Advances in novel immunotherapies and molecularly-targeted agents have raised interest in the field of in vitro cancer mimetic platform. As the need for understanding metastasis mechanism increases, various researches have been performed to develop a natural cancer tissue-like in vitro platform. Since immunotherapies and cancer metastasis are closely related to the circulatory system, the incorporation of vascular structure into the in vitro cancer mimetic platform could be a important factor. Decellularized lung ECM is a useful source for mimicking microenvironment of a natural lung, because ECM components and pro-angiogenic factors can instigate vascularization. We developed a novel 3D vascularized lung cancer-on-a-chip using ldECM and collagen hydrogel mixture. Specifically, a A549 spheroid for simulating lung cancer was encapsulated in the hydrogel with lung fibroblasts and endothelial cells. Two channels were fabricated to bio-mimick perfusable vessel structures.