Citrus fruits are the most important crop in the Valencian agriculture. The mean annual production usually overpasses the 3.500.000 tons. In economic value, this implies almost 50% of the final agriculture production of Valencia. Several pesticide residue monitoring programs at harvesting time were performed in order to know the real situation, to watch over the accomplishment of the normative; detect potential problems and intend to solve them. More than 500 citrus fruit samples/year are taken (from about 1000 samples/year, from fruit and horticultural products) from different varieties, proportionally to their production volume, seasonability and geographic distribution. The results showed that the most part of the samples, residues were detected (more than 70%), only in few cases (1.2 %) the maximum residue limits (MRL) of the Spanish legislation, were surpassed. Other works are dissipation curves and soil and water contaminations from herbicides were studied. Finally specials programs, for export of clementines to USA and Integrated Production were carried out with the purpose of putting up the price of citrus production, as well as the environmental contamination is reduced and also the fruit residue content.