Abstract: HPLC was applied to the determination of t-butylhydroquinone in edible oil. The edible oil sample (0.500 0 g)was extracted ultrasonically twice with acetonitrile (2 mL each). The combined extract was made up to 5 mL with mobile phase. C₁₈ chromatographic column was used as stationary phase, and a mixture of acetonitrile and water (7+3) was used as mobile phase. Detection at 290 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of t-butylhydroquinone was kept in the range of 1-150 mg·L^-1, with detection limit (3S/N) of 0.1 mg·L^-1. The proposed method was applied to the analysis of edible oil samples, giving values of recovery in the range of 93.5%-98.5%, intra-day RSD (n=6) of 1.8% and inter-day RSD (n=10) of 2.9%.