Antibiotics have been extensively and effectively used in human and veterinary medicines. Their benefits have been recognized in agriculture, aquaculture, bee-keeping, and livestock as growth promoters. This paper collects information from several investigations on the sources and occurrences of antibiotics in natural and artificial environmental systems. Several antibiotics were reported for their occurrences in water resources, effluent from industries, sludge, manure, soil, plants, and organisms across the globe. Sorption, photo-degradation, biodegradation, and oxidation were recognized as the main elimination pathways for these compounds and have been discussed in detail. The adverse effects of the pollutants were also highlighted and necessary suggestions were made for effective monitoring and mitigating pollution, which may provide the scope for future research. Potential pathways for antibiotics to enter the environment include release from manufacturing facilities, disposal of unused antibiotics by patients, hospitals, or distributors either to wastewater or to solid waste, patient excretion of and their metabolites to wastewater, use in aquaculture and animal farming. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.