Among the emerging environmental contaminants, pharmaceutically active compounds have become a growing public concern because of their potential to cause undesirable ecological and human health effects. Donana Park (South of Spain) includes a mosaic of unique ecosystems known around the world which is particularly affected by the quality of the incoming flowing water. This study reports the presence of a number of priority pharmaceuticals in wastewater and surface water samples from Donana watersheds. In general, ibuprofen, naproxen, salicylic acid, propranolol, caffeine and gemfibrozil were the compounds most frequently found in all locations, in the range of ng/L to mu g/L. Carbamazepine, with high potential risk to the environment, was also detected, although only in a few water samples. The main results are: (i) pharmaceuticals, as water pollutants, are continually discharged into Donana water bodies and, owing to their biological activity, could lead to adverse effects in this outstanding aquatic ecosystem; (ii) wastewater treatments implemented in the area are insufficient to remove pharmaceuticals; and (iii) therefore, there is a requirement for better wastewater treatments in this natural area to reduce or avoid the presence of organic pollutants in general and pharmaceutical active compounds in particular. To the best of our knowledge, these data constitute the first measurements of pharmaceutical compounds in water not only from the protected area of Donana Park but also from other Natural or National Parks in the world. (C) 2010 Elsevier B.V. All rights reserved.