Abstract: The urine samples of smokers were prepared by a self-designed extraction vial. UHPLC-MS/MS was applied to the rapid determination of nicotine and cotinine in the extract. Waters ACQUITY UPLC BEHHILIC chromatographic column (50 mm×2.1 mm, 1.7 μm) was used as stationary phase, and methanol (6+4) solutioncontaining 0.1% (mass fraction) ammonia was used as mobile phase; positive ionization was used in MS/MS. D₄-nicotine and D₃-cotinine were used as internal standards. Linearity ranges of nicotine and cotinine were found in the same range of 20.0-2 000 μg·L^-1, with detection limits (3S/N) of 5.7,3.7 μg·L^-1, respectively. Tests for recovery were made by standard addition method at the concentration levels of 2.0, 4.0, 8.0 μg. Values of recovery were in the range of 93.6%-112%, and values of intra-day RSDs (n=7) and inter-day RSDs (n=7) of determined values were in the range of 2.9%-3.4% and 3.2%-3.6%, respectively.