The aim of the work was the estimation of HPLC and GC/MS methods usefulness for the quantitative determination of phenylalanine in low protein cereal products (LPP). LPP products from two different producers (A and B), and related traditional products were investigated. The protein content was analysed with Kiejdahl method and the phenylalanine concentration was measured with high performance liquid chromatography (HPLC) coupled with UV detector (UV = 214 nm) and by the method of gas chromatography connected with mass spectrometry (GC/MS) using the ‘EZ:faast’ amino acid test (Phenomenex). The content of the amino acid was analysed after acid hydrolysis (6 M HCl, time: 24 and 48 h, temperature 110°C). The content of protein was determined higher than the producer’s declaration for all products of the producer B and some of the producer A. The higher protein content did not influence the concentration of phenylalanine detected with HPLC. Phenylalanine level was found below the declaration of the producer in most of the products. In most cases, there was no significant influence of the hydrolysis time on the quantity of the analysed phenylalanine.

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