Awareness of presence of the pharmaceuticals, especially of antibiotics in the environment has been of growing concern in past years. Numerous studies have shown their harmful effect on the environment, particularly on aquatic flora and fauna. But, increasing antibiotic resistance on antibiotics that have been the only „defence“ against many, often deadly bacteria, is probably the biggest problem which presence of antibiotics in environment has caused. At the same time, legal restrictions for limitation of pharmaceuticals and antibiotics release and their limit concentrations in surface and ground water, agricultural and other soils, and most important, in drinking water, has not been adopted yet. The most important route of entry for antibiotics in the environment is through effluents of communal waste water treatment plants, where they can not be removed during purification processes. Therefore, of greatest importance is implementation of researches to determine environmental concentrations and classes of the most common antibiotics, together with research of potential methods for their removal. This is especially important for Croatia, because it has one of the highest antibiotic consumption in Europe. Antibiotics that have been found in waste water of Croatian larger cities are the ones with greatest stability and potential harm. However, a systematic study of the concentrations of antibiotics and pharmaceuticals in Croatian surface and ground water has not been found. In this master thesis, the application of the Fenton process and adsorption on activated carbon and two zeolites, for the removal of antibiotics amoxicillin and norfloxacin from model waste waters, has been investigated. Optimal conditions for both methods and adsorbents were determined, together with complete evaluation and comparison of their efficiency. Fenton process and adsorption on activated carbon provided complete removal of antibiotics and proved to have great potential for further modifications, combination with other methods and applicability in practice.