Human and animal health have greatly benefited from antibiotics and the subtherapeutic dosages of antibiotics being routinely given to livestock to increase weight gain. However, concern exists regarding the potential link between antibiotic usage and the increased number of infections from antibiotic-resistant pathogens that have been observed in both humans and livestock.  Several studies have shown that antibiotics are transported in surface water and groundwater from both agriculture and urban sources.  A national stream-water reconnaissance conducted by the U. S. Geological Survey (USGS) documented that at least one antibiotic was present in approximately 50 percent of the samples analyzed with concentrations in water typically less than 0.5 μg/L.  In 2003, USGS initiated a streambed-sediment reconnaissance followed by a source reconnaissance in 2004 during which wastes were collected in the United States from a variety of human and animal sources and analyzed for a broad suite of pharmaceuticals and organic wastewater contaminants that included antibiotics.  An extraction method was developed and validated for antibiotics in biosolids, manure, soils, and streambed sediment.  These residues were detected using online solid-phase extraction liquid chromatography electrospray-tandem mass spectrometry.  Preliminary results from the streambed reconnaissance and the source reconnaissance indicated that antibiotic residues typically were greatest in biosolids and manure where concentrations frequently exceeded 50 μg/kg in a 1-gram sample (dry weight) whereas, streambed sediment and soil concentrations were much more variable with concentrations usually less than 20 μg/kg.  The distribution of antibiotics in streambed sediment and source materials from urban and agricultural influences will be discussed.