2,3,5,6-Tetrafluorophenyl 3-(nido-carboranyl) propionate (TCP), as a new potential bi-functional linker for radiohalogenation of proteins or peptides, was synthesized. With this bi-functional linker, the first attempt to conjugate bovine serum albumin (BSA) with (125)I was made and the biodistribution of the conjugated BSA ((125)I-TCP-BSA) was investigated in NIH strain mice. By the use of TCP as the linker, BSA was conjugated with (125)I in a labeling yield of 58-75% and with radiochemical purity of 99.8% after purification by Sephadex(TM) G-50. Even after being kept at room temperature for 72h, the radiochemical purity of (125)I-TCP-BSA was still more than 98%, much higher than that of the directly (125)I-labeled BSA ((125)I-BSA). Meanwhile, biodistribution experiments in mice indicated that the uptake of (125)I with (125)I-TCP-BSA into thyroid was obviously less than that with (125)I-BSA post-injection. All the results implied that the (125)I-conjugated BSA ((125)I-TCP-BSA) was considerably stable in vivo as well as in vitro, and TCP was regarded as a promising bi-functional linker for radiohalogenation of proteins.