A method for identifying a molecule that binds an irradiated tumor in a subject and molecules identified thereby. In some embodiments, the method includes the steps of (a) exposing a tumor to ionizing radiation; (b) administering to a subject a library of diverse molecules; and (c) isolating from the tumor one or more molecules of the library of diverse molecules, whereby a molecule that binds an irradiated tumor is identified. Also provided are targeting ligands that bind an irradiated tumor and therapeutic and diagnostic methods that employ the disclosed targeting ligands.