For many years pharmaceuticals have been used for medical therapeutic purposes and therefore have been uncontrollably entered in the environment, through excretion, inappropriate disposal or because of inadequate waste water treatment plants. Recently they have been recognized as a potentially harmful pollutants, so accordingly that the term "emerging contaminants" have been formed. There is still no sufficient data to predict their behavior and the impact on the environment. That is reason for increasingly investing in the development of instruments with sufficiently low limits of detection and quantification, to determine the threshold limit value of pharmaceuticals in the environment. Many studies have pointed to a possible biodegradation of these compounds, so that can be set in systems for waste water treatment. The aim of this study was to optimize the conditions of biodegradation veterinary pharmaceutical anthelmintic albendazole in a batch reactor by monitoring the physical and chemical parameters in water media. The effectiveness of biodegradation of albendazole and identification of transformation products formed during the process is monitored by analytical and bioanalytical methods. In this study the biodegradation of albendazole in the water with activated sludge have been achieved whereby it could not be ignored the impact of hydrolysis on that process. Transformation products have been detected and identified by high performance liquid chromatography and ultrahigh performance liquid chromatography, and assessment of toxicity of biodegradation process was made by measuring the zone of inhibition on microorganisms characteristic for soil and water.