Isotianil (3,4-dichloro-2'-cyano-1,2-thiazole-5-carboxanilide) is a new plant-activating pesticide. Usage of the pesticide was approved for rice fields in 2010 and its production increased 400 times (2 × 10(4) kg) in the next year. In this work, a method for determining isotianil in brown rice and rice field soil was investigated for the first time. Isotianil was extracted by supercritical fluid extraction and measured by gas chromatography/mass spectrometry. Isotianil was successfully analyzed with good recoveries (95.1-99.3%) even from soil samples with strong adsorption of pesticides.