This study performed to investigate the changes in S-allyl-L-cysteine (SAC) content of garlic with different cooking methods. Methods for determining SAC was validated by determining specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy using HPLC-FLD system. Results showed high linearity in the calibration curve with a coefficient of correaltion (R 2 ) of 0.9999. The LOD and LOQ values for SAC were 0.15 and 0.49 μg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precision of SAC were less than 5%. The recovery rate of SAC was in the range from 97.35% to 97.47%. The SAC content of raw garlic was 2.77 mg/g, and there are no significantly difference among blanching and microwave treatment in SAC content. However, SAC content of boiling, autoclaving at 110℃ and 121℃ increased in the range of 3.50~9.19 mg/g, 6.52~16.21 mg/g and 14.15~50.24 mg/g as increasing cooking temperature and time, respectively.