The study contributes with a first survey of pharmaceuticals in municipal wastewaters discharging into fresh and estuarine waters from areas with varying degrees of urbanization of Argentina. Analyses were done on the soluble fraction by HPLC–MS after SPE extraction. In all of the samples were detected caffeine and ibuprofen within the range of 0.9–44.2 and 0.4–13.0 μg/L, and lower levels of carbamazepine, atenolol and diclofenac between 0.2–2.3, 0.2–1.7 and <0.03–1.2 μg/L, respectively. Profiles of compounds were similar in all studied locations.Centro de Investigaciones del Medioambient