[en] Total arsenic concentrations (t As) and the presence of total and fecal coliforms in drinking water from Tecuala, Nayarit, Mexico, were determined. The presence of t As was analyzed by means of hydride generation atomic fluorescence spectrometry. Total and fecal coliforms were determined through the Most Probable Number (MPN) method. According to the results, the mean concentration of t As in Tecuala wa 15.82 μg/L, in Atotonilco 19.88 μg/L, in Pajaritos 21.49 μg/L, in Quimichis 17.80 μg/L, and in Playas de Novillero 19.79 μg/L. The t As concentrations in drinking water from Tecuala, Nayarit, are within the limit set by the Mexican official standards (25 μg/L); still, they are over the limit established by the World Health Organization (10 μg/L). The concentration of coliforms in water from wells 1 and 3 was 180 MPN/100 ml and 43 MPN/100 ml for well water 2. The presence of total and fecal coliforms, suggest the infiltration of sewage which could increase the levels of dissolved arsenic. The results of this study will serve as an antecedent of the water quality in Tecuala, Nayarit. (Author)