The synthesis of D- and L-selenomethionine labeled with ⁸²Se and three deuteriums at Se-methyl group (D- and L-[²H₃, ⁸²Se]selenomethionine) was described. D- And L-[²H₃, ⁸²Se]selenomethionine were prepared by condensation of (R)- and (S)-2-amino-4-bromobutylic acid with lithium [²H₃, ⁸²Se]methaneselenolate, which was prepared from metal (82)Se and [²H₃]methyl iodide. The optical purities of D- and L-[²H₃, ⁸²Se]selenomethionine were determined by HPLC with a chiral stationary phase column and were found more than 99% ee. The chemical ionization mass spectra showed that the molecular related ion for N-isobutyloxycarbonyl ethyl ester derivatives of [²H₃, ⁸²Se]selenomethionine did not overlap with the m/z values known from that of non-labeled selenomethionine.