The acid functionalized-multiwalled carbon nanotubes (FMWCNTs)-nanostructured 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) composite film was fabricated on glassy carbon electrode (GCE) for the sensitive determination of rutin (Rut). The composite film was characterized by SEM, FT-IR, attenuated total reflectance (ATR)-FT-IR, XPS and cyclic voltammetry. The attachment of FMWCNTs on the electrode surface through amide bond formation was confirmed from the C1s peak at 287.3 eV in XPS and the band at 1681 cm(-1) in ATR-FT-IR spectroscopy. The FMWCNTs-AMT composite film was then exploited for the determination of uricase inhibitor, rutin (Rut) in 0.2 M phosphate buffer solution (pH 3). The oxidation of Rut at composite electrode occurs with 30 mV less positive potential and 3.2-fold higher oxidation current when compared to bare GCE. The amperometric current response was increased linearly when Rut concentration was increased from 10-1000 nM and the detection limit was found to be 0.3 nM (S/N=3). Further, the composite modified electrode successfully determined the concentration of Rut in the presence of 250-fold higher concentration of one of the major interferents, ascorbic acid. The practical application of the present modified electrode was demonstrated by determining the concentration of Rut in tablets. (C) 2015 Elsevier Ltd. All rights reserved.