The world population of 6.8 billion people all produce sewage. In the developed world most of this is treated by the activated sludge process, which results in large volumes of sludge or biosolids being produced (NRC, 2002). This results in millions of tons of biosolids produced each year in the United States, which must either be disposed of or recycled in some manner. Land application has been seen as the most economical and beneficial way of handling biosolids. Biosolids that result from municipal wastewater treatment processes contain organic matter and nutrients that, when properly treated and applied to farmland, can improve the productivity of soils or enhance revegetation of disturbed ecosystems. However, besides the documented benefits of land application, there are also potential hazards, which have caused the public response to the practice to be mixed. Here we review one of the potential hazards associated with biosolids and its land application, namely human pathogens associated with biosolids.