Abstract: The precise determination of selenomethionine (SeMet) in wheat flour has been performed by species specific isotope dilution mass spectrometric analysis (IDMS) using an inductively coupled plasma mass spectrometer as detector after liquid chromatography (LC-ICP-MS). A labeled ⁷⁶SeMet species-specific isotope enriched spike solution was used for these determinations. The experiment procedure included spiking, extraction, and a simultaneous separation and detection procedure. The method gave yield to good precision (＜2%). The accuracy of the method has been validated on the certified reference materials. The result obtained was in good agreement with the certified reference value. And this method was used to do the international comparison CCQM-K60.