A rapid and effective method for the simultaneous determination of cyflumetofen and its main metabolite residues in samples of plant and animal origin (tomato, apple, eggplant, soybean, green tea, fish, and pork liver) was developed using ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples were extracted with acetonitrile and cleaned-up with multi-walled carbon nanotubes (MWCNTs). The determination of the presence of target compounds was achieved in less than 4.0 min using an electrospray ionization source in the positive mode (ESI+) for cyflumetofen and 2-(trifluoromethyl) benzamide (B-3) and the negative mode (ESI-) for alpha,alpha,alpha-trifluoro-o-toluic acid (B-1). The entire method was validated by evaluating the repeatability, linearity, precision, trueness, and matrix effect. Average recoveries of the analytes were in the range of 79.3-117.6% with relative standard deviation values below 7.6%. Limits of quantification (LOQs) ranged from 0.7 to 9.8 mu g kg(-1), which were lower than the maximum residue limits (MRLs) for the cyflumetofen found in foods in Japan. (C) 2013 Elsevier B.V. All rights reserved.