Single cell gel electrophoresis, the so-called "Comet" assay, was performed as a genotoxicity test in white storks sampled in an area heavily contaminated after the ecological disaster in south western Spain. This disaster occurred as a consequence of a massive toxic spillage of acid waste rich in heavy metals that impacted on the Doñana National Park. The importance of this protected area as a breeding and wintering site for many endangered bird species makes this analysis of DNA damage of special interest. Our results clearly show that white storks born in the contaminated area 1 year after the toxic spill bear a high burden of genetic damage as compared with control individuals. The possible implications for future survival as well as reproductive rate are discussed.