Blood vessels are responsible for transporting blood throughout the body as part of the circulatory system. Their main components are endothelial cells, which comprise the inner lining, and mural (or perivascular) cells, which are largely responsible for regulating vasoconstriction, pruning, permeability, and vascular maturation. There are two main types of mural cells: vascular smooth muscle and pericytes. Pericytes wrap around capillary vessels and communicate with other cells using their long cytoplasmic processes. Vessels that lack or have lost pericyte investment are shown to become hemorrhagic or hyperdilated. Unlike vascular smooth muscle cells, pericytes have roles beyond scaffolding evidenced by their direct communication and physical contact with endothelial cells, and their density differs with respect to their function and capillary bed. Among their many functions, pericytes most notably contribute to blood brain barrier functionality and their loss has been found to contribute to neurodegenerative diseases and stroke. ScienCell™’s 3D Endothelial-Pericyte Coculturing Kit (3D-EPC) combines both pericytes and endothelial cells in one 3-dimensional in vitro assay that utilizes a defined serum-free medium to mimic the vasculature more closely in a controlled environment (see Figure 1 at end of protocol).