STEMdiff™ Branching Lung Organoid Kit (Catalog #100-0195) is a serum-free medium system for efficient and reproducible generation of branching lung organoids from human embryonic stem (ES) and induced pluripotent stem (iPS) cells through four stages of differentiation: 1) definitive endoderm, 2) anterior foregut endoderm, 3) lung bud organoid, and 4) branching lung organoids. STEMdiff™ Branching Lung Organoid Kit has been optimized for differentiation of cells maintained in mTeSR™1 (Catalog #85850). Resulting organoids will develop proximal and distal-like branching airway epithelial structures expressing EPCAM, NKX2.1, SOX2, SOX9, MUC1, and P63. When maintained beyond 28 days in a Matrigel® sandwich, there is an increase in expression levels of markers for more mature lung cells, such as SFTPC, SFTPB, and ABCA3. For extended periods of organoid culture (> 28 days in the Matrigel® sandwich), the components required for branching lung organoid maturation are available in STEMdiff™ Branching Lung Organoid Maturation Kit (Catalog #100-0528).