Endocrine disrupting compounds (EDC) are chemically diverse and ubiquitous compounds which are released into the environment as a result of industrial, domestic and agricultural processes. They are generally readily absorbed from ingested food and water, can accumulate in animal tissue and can have adverse effects on reproductive and immune systems at very low concentrations. They are present in high concentrations in sewage sludge which is likely to be used increasingly as a fertiliser on pasture and arable land and so there is potential for bioaccumulation in animal tissues and associated, adverse biological effects. The aim of the study was to determine the concentrations of one EDC, dioctyl phthalate (DOP), in the livers of ewes and lambs maintained on control and sludge-treated pastures.