Moulds of the genus Penicillium, Apergillus and Fusarium are among the most common causes of food contamination, producing mycotoxins as toxic secondary metabolites in unfavorable conditions, which can be very dangerous for humans. The purpose of this reasach was to determine the presence and amount of total aflatoxins, ochratoxin A and fumonisins B1 and B2 in diferent cereals, and check whether they are in accordance with the prescribed maximum permissible concentration. Analyzed samples of corn, rice, semolina and food for children based on cereals in an approved laboratory of the University of Valencia by liquid chromatography and tandem mass spectrometry (LC-MS/MS). Based on the analysis, alfatoxins are present in all samples, one of the seven sample of corn almost twice exceeds maximum permissible concentration of aflatoxin G1. The infant food based on cereals aflatoxins are present in two out of nine samples that exceed the maximum permissible concentration, as well as a sample of ochratoxin A with up to 4,0 ng/g at permitted 0,5 ng/g. The other samples are determined levels within the maximum residue levels. In order to achieve safe food production, continuous development of new methods for the detection and reduction of mycotoxins contamination, as well as the systematic monitoring on a representative number of samples of food, are required.