Since their discovery, antibiotics have been instrumental in treating infectious diseases that were previously known to kill humans and animals. However, it has now become clear that widespread use of antibiotics is not without problems. The major concern is the development of antibiotic-resistant microorganisms, which are difficult to treat with existing antibiotics. It is claimed that a significant portion of the antibiotic produced (as high as 78%) is used as feed supplement in food animals. The use of antibiotics in animal feed helps increase the animal's ability to absorb feed and thus reach market weight quicker. In addition, supplementing antibiotics in animal feed counteracts the effects of crowded living conditions and poor hygiene in intensive animal agriculture. Although antibiotic dose is small (1 to 200 g per ton of feed), as much as 80% the antibiotic may pass through the animal in urine and manure unaltered. Since much of the manure is land applied, there is concern not only on the spread of antibiotic resistant bacteria to the environment but also on the potential of antibiotics appearing in water and food supplies. This presentation summarizes the results of studies on (1) the extent of antibiotic losses in surface runoff and through leaching from manure-applied lands, (2) sub-therapeutic feeding of antibiotics in food animals and development of antibiotic resistance on the farm, and (3) plant uptake of antibiotics from manure applied soils.