Abstract: Blood sample (0.50 mL) was mixed with 0.3 mL of ammonium acetate buffer solution (pH 10), and the mixture was purified on the supported liquid extraction column and 8 mL of dichloromethane was used as eluent. The treated eluate was separated by HPLC using Kinetex C₁₈ column as stationary phase and mixtures of acetonitrile and 0.1% (φ) formic acid solution containing 5 mmol·L^-1 ammonium acetate, mixed in various ratios, as mobile phase in gradient elution. ESI⁺ and MRM were adopted in MS. Linear relationships between values of peak area and mass concentration were found in the ranges of 0.20-10.00 μg·L^-1 for zolpidem and 1.00-50.00 μg·L^-1 for zaleplon, with detection limits (3S/N) of 0.02, 0.10 μg·L^-1, respectively. Test for recovery was made by standard addition method, giving results in the range of 85.0%-103%, with RSDs (n=6) ranged from 3.5% to 8.5%.