Nowadays, the scientific community has focused and prioritized research on “emerging pollutants”. The term “emerging pollutants” stands for the substances that are released in the environment for which currently no regulations are established for their environmental monitoring. Their occurrence is reported worldwide in a range of aquatic environments, such as lakes, rivers, freshwater catchments, estuaries, reservoirs and marine waters. Nevertheless, due to their large number (ranging in an order of thousands), only few of these compounds are toxicologically evaluated. Published data concerning occurrence and potential toxicological effects is limited. The contamination source of the aquatic environment is mainly the effluents from the sewage treatment plants (STPs). Reliable methods are available for residue analysis of these pollutants down to low ng/L levels. However, an urgent need is highlighted for the investigation (primarily in environmental media and following in biological ones) of the toxicity and transformation pathways of all emerging pollutants. The aims of this mini-review are to briefly present: (a) the major classes of emerging pollutants; (b) the reasons why these substances constitute an environmental issue; and (c) developments and applications of environmental analysis in this field.