Mycotoxins are secondary metabolites produced by few fungal species that readily colonize crops and contaminate them with toxins in the field or after harvest. Surveillance studies have showed that mycotoxin contamination is a world-wide problem, since it is estimated that 25% of the world's crop production and 20% of crop production within the European Union may be contaminated with these contaminants. Economic losses deriving from that are tremendous, including reduction of livestock production and agricultural production, health care, veterinary and regulatory costs. The methods described in this Thesis for the extraction of mycotoxins from cereal and derivates used conventional techniques such as solid-liquid extraction (SLE), solid-phase extraction (SPE) and immunoaffinity columns (IACs). However, matrix solid-phase dispersion (MSPD) and modified QuEChERS were used as alternative extraction methods. Finally, and after appropriate extraction method, mycotoxins into the extract have to be identified and quantified. A method of analysis for mycotoxins in food should be simple, rapid, robust, accurate and selective to enable simultaneous determination of mycotoxins. The currently used quantitative methods for the determination of mycotoxins in food mainly use chromatographic techniques for separation, in combination of a variety of detectors. HPLC with different detectors is frequently used both for routine analyses and as confirmatory method or screening techniques. Nowadays, the most widely used spectrometer in mycotoxins analysis has been the triple quadrupole, although QTRAP and Orbitrap technology were used in this Thesis in order to improve qualitative data. At the end, the regular presence of low levels of mycotoxins in several foods has been clearly demonstrated. Therefore, estimation of risk in terms of daily intake was calculated, in all the cases the daily dietary intake was below the tolerable daily intake established.