There is a growing need for biocompatible materials suitable for the engineering of blood vessel replacements for the treatment of vascular disease. In this issue, Huynh et al. have fashioned scaffolds for such surgical replacements, derived from collagen biomaterial harvested from the submucosal layer of the small intestine (see p. 1083). Within three months, the engineered grafts integrated into the host tissue, became recellularized by endogenous smooth muscle and endothelial cells, and were responsive to vasoactive factors.