Sensitive non-invasive or intraoperative imaging techniques can improve the management of patients with cancer. In tumor-targeted imaging targeting vehicles like monoclonal antibodies are used that specifically recognize tumor-associated antigens. When a radionuclide or a fluorescent molecule is conjugated to a tumor-targeting monoclonal antibody, a tumortargeting imaging tracer is created that can be used to visualize the primary tumor or metastases with, for example, Positron Emission Tomography (PET), Single-Photon EmissionComputed Tomography (SPECT) or fluorescence imaging. In this thesis several preclinical and clinical applications of radiolabeled and/or fluorescently labeled antibodies have been investigated aiming to translate tumor-targeted imaging to the clinic.