Abstract: 90Y is a useful radionuclide for radiotherapy due to its energetic β- ray(Emax=2.3 MeV)and favorable halflife(T1/2=64 h) and it can be obtained from 90Sr90Y generator for the carrierfree form. The radiolabeling methods, toxicity and dose estimation in animal and clinical application for the cancer treatment with 90Y labeled monoclonal antibodies and peptidereceptor are summarized.