Abstract: A method for determination of ethyl carbamate in fermented dairy products was proposed by gas chromatography-mass spectrometry (GC/MS) with deuterium ethyl carbamate as isotopic internal standard. The types and times of extraction solvents were discussed to establish efficient pretreatment method. The results show that the calibration curve has good linearity in the range of 0.05-20 mg/L with the correlation coefficient of 0.999 8, and the limit of detection is 0.02 mg/L. The recoveries range from 98.9% to 102.9% with RSDs of 0.6%-4.8% in three levels. The method is simple, rapid, accurate, and can be applied in the quantification of ethyl carbamate in fermented dairy products.