The production, use, environmental fate, occurrence, and toxicity of perfluoroalkylated substances have been reviewed. Although only a limited number of essential physicochemical data are available, thus hampering a complete assessment of the environmental fate of PFAS, it has become clear that PFAS behave differently from other nonpolar organic micropollutants. PFAS are present in environmental media in urbanized areas both with and without fluorochemicals production sites. The presence of PFOS at levels above the limit of detection has been demonstrated in almost all organisms sampled in a global survey as well as in both nonexposed and exposed human populations. The acute and chronic ecotoxicity of PFOS, PFOA, and 8:2 FTOH to aquatic organisms is moderate to low. Acute toxicity to rodents is also low. PFOS concentrations in effluents have been reported that approach indicative target values derived from available aquatic toxicity data. PFOA has been found to be weakly carcinogenic. This review shows the importance of the perfluoroalkylated substances for the environment and the necessity to fill the current gaps in knowledge of their environmental fate and effects.