The present invention is based on the discovery of new methods for obtaining a tissue graft. The method can be carried out, for example, by implanting a biocompatible scaffold into a mammal and then removing the scaffold from the mammal. The scaffold is implanted in direct contact with (i.e. physically touching over at least a portion of its external surface), or adjacent to (i.e. physically separated from) mature or immature target tissue, for a period of time that is sufficient to allow cells of the target tissue to associate with the scaffold. The invention also features grafts generated by the methods described herein and methods for using those grafts to treat patients who have a defect in a target.