Urban wastewater treatment plants (UWTPs) have a pivotal role in the protection of the environment, in particular, the natural water bodies. The removal of organic matter, chemical pollutants and undesirable microorganisms from sewage, using combinations of physicochemical and biological treatments, was a major technological achievement of the last century, allowing the return to the environment of water with good quality. However, the final UWTPs effluents are far from being sterile and, hence, release to the environment high amounts of bacteria, many of which are of animal (e.g. pets or small husbandry or animal farms) or human origin (Berendonk et al., 2015; Manaia, 2017; Rizzo et al., 2013). Many of these bacteria harbour acquired antibiotic resistance genes (ARGs) and are potential carriers for the dissemination of these genes in the environmental microbiome (Berendonk et al., 2015; Manaia, 2017; Pruden, 2014). As such, these bacteria are considered a potential threat to humans and/or animals health since they may lead to more cases of difficult-to-treat infections. Moreover, although only part of the ARB released from UWTP will be able to cause disease in humans or animals, the risk of enriching the environmental resistome either through selection or horizontal gene transfer (HGT), and therefore contribute to the emergence of resistance in pathogenic bacteria cannot be neglected (Manaia, 2017). UWTPs bring together antibiotic resistant bacteria (ARB), antibiotic residues and other potential selectors that favour the selection towards these bacteria and, simultaneously, offer a rich supply of nutrients and close cell-to-cell interaction, capable of facilitating the horizontal transfer of ARGs. These arguments make the UWTPs environment one of the most exciting niches to unveil the fate of ARB&ARGs. This paper is the result of a think tank of Early Stage Researchers summer school organized by the Marie Skłodowska-Curie Innovative Training Networks, project ANSWER (http://www.answer-itn.eu/), and discusses the tools and the environmental conditions that may rule the fate of ARB&ARGs throughout the wastewater treatment. The paper is divided into four major sections: 1) one dissecting the UWTPs compartments where analyses of ARB&ARGs may be relevant given the potential constraints that are imposed to the microbiota, as well as 2) the bio-physico-chemical conditions that may shape the dynamics of populations and genes within the bacterial communities; 3) another revising the pros and cons of the most commonly used methods to analyse antibiotic resistance in environmental samples; and 4) a final section where the previous three are combined to give an integrated overview of the major information on ARB&ARGs ecology, exemplified through the answers to some frequently asked questions. Above all, this work intends to serve as a guide for wastewater professionals who aim at optimizing wastewater treatment for the removal of ARB&ARGs.