A non-suppressor ion chromatography method (IC) with a diode array detection (DAD) was applied to determine the content of nitrates(III) and nitrates(V) in selected food products. An experimental material consisted of potable spring water, fresh vegetables, and meat products. A method of preparing samples for analysis was modified so that the sample purification and deproteinization stages were removed and the extraction process was enhanced. At the same time, optimal conditions for chromatographic separation were selected. The limits of detection for sodium nitrate(III) and sodium nitrate(V) by the IC-DAD method were, respectively: 0.02 and 0.05 mg·kg^-1. Then, the limits of detection for nitrates(III) and (V) were, respectively: 0.06 and 0.15 mg·kg^-1. Based on the results of the authors’ own analyses and on interlaboratory analyses, it was found that the method developed on the basis of IC-DAD technique could be applied to determine the content of nitrates(III) and nitrates(V) in food products. Using the method adapted by the authors, it is possible to determine the nitrates(III) and nitrates(V) with an accuracy level ≤ 5 % and with the recovery level of 90 – 110 %. The method developed is so universal that it can also be used in the analyses of complex food matrices as an alternative for classical spectrophotometric methods.