Abstract: The raticide fluoroacetamide (FAA) is detected by HR-TOF-MS using flow injection (FI). The FAA is first hydrolyzed with 10% amonia in boiling water bath to produce fluoroacetic acid, and fluoroacetic acid as the hydrolysis product is detected. The mass deviation is less than 1 mD (77.004 5 vs 77.003 9) with 5-sulfosalicyic acid as calibration mass. The only possible mass interference within ±10 mD is C 2H 6OS which can be identified by its M+2 peak abundance. 10 μg/g FAA in rice bait can be detected. The parameters of TOF-MS are discussed. There is no interference in blank rice. The whole procedure from sample preparation to FI-TOFMS detection can be finished within 1 h.