Abstract: A method of hyphenated GC-MS with selected ion monitoring(SIM) for the determination of specific nitrosamines of tobacco,including N′-nitrosomor-nicotine(NNN) and 4-(N-nitroso-methylamino)-1-(3-pyrigyl)-1-butanone(NNK),in mainstream smoke of cigarette was studied and reported in this paper.The cigarette smoking particulates were collected on a Cambridge filter with a machine under standard smoking conditions.The collected matter was co-extracted with mixture of citrate-phosphate buffer and cyclohexane and then purified on alkaline Al2O3 column and by solid-phase extraction.Identification and quantification of the analytes were performed by the selected ion monitoring technique.Detection limits of the method found were 9.83 μg·L-1 for NNN and 16.92 μg·L-1 for NNK.Linearity was in the range of 0.1-5.0 mg·L-1 with correlation coefficient of 0.998,0.996 and recovery of 91.0%,94.8% respectively.