A method for creating networks of perfusable microvessels in vitro. Cells including cell types capable of sprouting are seeded 1300 into a channel in a matrix at to activate competency 1304 of the cells for sprouting as microvessels based on the seeding density. The matrix channel is perfused with medium to allow parent vessels to form and for viability 1324. The parent vessels and matrix are incubated and perfused to provide for sprouting of microvessels from parent vessels into the surrounding matrix 1328. The sprouting parent vessels are grown until network forms 1332.