A new method for determination of fumonisins in corn samples was developed and validated. The mycotoxins were extracted by a mixture of methanol-acetonitrile-water (1:1:2, v/v/v) and determined on a liquid chromatograph with mass spectrometric detection. The separation was performed on Zorbax XDB-C(18) column (150 x 4.6 mm; 5 microm) with a Metaguard ODS-2 precolumn (30 x 4.6 mm; 5 mum) using gradient elution with mobile phase consisting of acetonitrile and 5 mmol/L ammonium acetate (adjusted by acetic acid to pH 3.0). For detection of (M+H(+)) ions, a quadrupole mass spectrometer in single ion monitoring mode was applied. Developed method showed very good linearity in a tested range of concentration. Detection limit is 62.0 microg FB(1)/kg and 58.5 microg FB(2)/kg of maize grains. Because the detection limits lie under the maximum permitted EU levels, the method is suitable for determination of fumonisins in milled corn grains.