Abstract: To develop a rapid method for determination of quinolones and tetracyclines in egg by liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide analytical methodology for the egg in Ningxia province, samples of eggs were ultrasonically extracted by EDTA-Mcllvaine buffer solution, filtrated by glass fiber membrane and then cleaned up by HLB column. Quinolones and tetracyclines were separated on Waters Atlantis T₃ chromatographic column with mobile phase of methanol-0.1% formic acid on gradientelution. Ionized by atmospheric pressure chemicalionization, the quinolones and tetracyclines were qualified and quantified by mass spectrometry. Average recoveries of quinolones and tetracyclines in egg at three spiked levels were 80.0%~114.0% and 84.5%~110.0% with relative standard deviations less than 12.0%, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) for the whole method were 0.2 μg/kg and 0.8 μg/kg, respectively. The method was accurate, reliable, and could be used as a quality control method for quinolones and tetracyclines in egg.