In order to investigate the comparative fates and dispositions of 4-acetyl derivative of NIV (Fusarenon-X, FX) in broilers and ducks, FX was administered either intravenously (i.v.) or orally (p.o.) to broilers and ducks. FX and its metabolites (nivalenol, NIV) in plasma and urine were determined using a Gas Chromatography- Mass Spectrometer (GC-MS). The plasma concentrations of FX were determined up to 180 and 120 min in both broilers and ducks, respectively after i.v. and p.o. administration. The active metabolite NIV was eliminated more slowly than its parent compound. FX disposition fitted an open two-compartment pharmacokinetic model in broilers and ducks. The elimination half-life (t1/2) of FX was longer in ducks than in broilers. The elimination rate constant (kel) was higher in broilers than in ducks whereas the oral bioavailability of FX was higher in ducks than in broilers. The GC-MS profile of acetonitrile extracts of plasma and urine showed that a large proportion of NIV after administration of FX either broilers or ducks. This study demonstrated that FX is absorbed more efficiently in ducks than in broilers, while FX is excreted more rapidly from broilers than ducks, markedly changed to NIV.