Abstract: A novel method for determining mirex and pyridaben residues in wax-apple (Syzygium samarangense(Bl.)Merr. et Perry) was developed by using gas chromatography-tandem mass spectrometry(GC-MS/MS) detection. The samples were extracted with acetonitrile. After cleanup on carbon/NH2 column with elution solvents of V (acetonitrile): V (toluene)=3:1 and further concentration, GC-MS/MS was used to analyze the samples. The average recoveries of 2 pesticides were 89%-102% at spiked levels of 0.01, 0.05, 0.1 and 0.5 mg/kg, with relative standard deviations (RSDs) in the range of 1.7%-5.2% (n=5). The calibration curve was linear in the range of 0.01-0.5 mg/L and coefficient of determination R2>0.99.The limits of quantitation (LOQ) for mirex and pyridaben were 0.005 mg/kg. The method is applicable for detection of mirex and pyridaben residues in wax-apple.