The Argentinian alcohol industry generates about 10 L of vinegar / L of ethanol as waste. (COD = 70000 ppm). Recent studies in vinasses report the presence of organochlorine pesticides (OC) belonging to the "Dirty Dozen", a group of nine pesticide substances potentially dangerous to the environment and human health, namely DDT, dieldrin, aldrin, endrin, chlordane, heptachlor, mirex, hexachlorohexanes, and toxaphene, the list is gradually increasing with other pesticide substances.Currently the effluent, after evaporation, is used as fertilizer and source of potassium in impoverished soils. The objective of the work was to validate a method that reliably quantifies the content of POs in vinasses in order to prevent their environmental recycling. The technique includes extraction, cleaning, concentration and chromatography. The validation consisted of establishing performance parameters from the injection of extracts, to the extrapolation of the results to samples of vinasse through recovery evaluations. The reference method was EPA 8080. Tests were planned to evaluate detection limits (LD) and quantification, linearity, precision, accuracy and recovery. The results obtained showed LD between 0.83 ppb (heptachlor) and 4.6 ppb (methoxychloro); appropriate linearity in the working range (average correlation factor of 0.995); Statistically acceptable accuracy and precision.