The present invention provides isolated, engineered multivalent antibody fragments that specifically bind αVβ6 integrin. In particular embodiments, the antibody fragments of the present invention further comprise an imaging agent and/or a therapeutic agent. In some instances, the antibody fragments also include unnatural amino acids and/or inserted cysteine or thiol residues at the C-terminus of the scFv molecules of the fragments. The anti-αVβ6 integrin antibody fragments provided herein are particularly useful for imaging a tumor, organ or tissue and for treating an αVβ6 integrin-mediated disease or disorder. Compositions and kits containing the multivalent antibody fragments of the present invention are also described herein.
