Methods of tissue engineering, and more particularly methods and compositions for generating various vascularized 3D tissues, such as 3D vascularized embryoid bodies and organoids are described. Certain embodiments relate to a method of generating functional human tissue, the method comprising embedding an embryoid body or organoid in a tissue construct comprising a first vascular network and a second vascular network, each vascular network comprising one or more interconnected vascular channels; exposing the embryoid body or organoid to one or more biological agents, a biological agent gradient, a pressure, and/or an oxygen tension gradient, thereby inducing angiogenesis of capillary vessels to and/or from the embryoid body or organoid; and vascularizing the embryoid body or organoid, the capillary vessels connecting the first vascular network to the second vascular network, thereby creating a single vascular network and a perfusable tissue structure.