The intensive use of pesticides has increased the risk connected with their presence as residues or metabolites in the environment and in underground water in many coun-tries, including Italy. These residues in underground water could represent an underestimated problem for consumer health, since polluted irrigating water can convey pesticides to foodstuff that is not supposed to be treated with those substances. In the present study, the water of irrigation wells in central Italy was analyzed for the content of a number of herbicides in different periods of the year. All water sam-ples were filtered through SPE ISOLUTE cartridges to remove impurities and analyzed using HPLC-UV and GC-MS instruments. The results showed the presence of some herbicides in most of the wells at very low amounts. The detected average concentration was below 0.1 µg kg -1 ; the highest concentration was that of Metolachlor, 12.5 µg kg -1 . Overall, contaminated wells were found in the whole area under study. The most frequent herbicides were Atrazine, Fluroxypyr, Metolachlor, and Terbuthylazine. Atrazine, which is commercially forbidden since many years, was present in very low and constant concentration over the monitored period (about 10% variation in 6 monthly analy-ses). On the contrary, Fluroxypyr, which is still widely used, showed a much higher concentration (almost 5 times) in un-derground water in September than in winter, with concen-tration values of 0.18 and 0.04 µg kg -1 , respectively.