Abstract. In 2006 our research group in the Department of Chemistry of the University of Athens (Greece) was researching antioxidant enzymes and lipid peroxidation in mussels in relation to toxic metal pollution in the Saronikos Gulf (Piraeus, Greece). Additionally, we published a review paper in Ecotoxicology and Environmental Safety:  Valavanidis A, Vlachogianni T, Dassenakis M, Scoullos M. Molecular biomarkers of oxidative stress in aquatic organisms in relation to toxic environmental pollutants. Ecotoxicol Environ Saf 64(2):178-189, 2006. The review gathered numerous citations in the scientific literature. Up to 23/3/2019 there were 1.260 citations in Google Scholar and 941 citations in Researchgate.  Now, 13years later we decidedtoreviewthe progress in the field of biomarkers of oxidative stress in aquatic organisms and new ecotoxicological studies from research papers until now. In the last decade there were many advances in multibiomarker approach of oxidative stress in aquatic organisms in relation to chemical pollutants or environmental stressors. Some of fhese assays have become a standard sentinel analytical tool (for open field or laboratory studies) for measurements of environmental pollutants and ecotoxicological risk assessment. This approach can detect directly exposed organisms to toxic xenobiotics at environmentally relevant concentrations. Molecular multibiomarkers of oxidative stress allow to identify adverse biological responses at different levels (from whole organism to tissues, cells, sub-cellular organelles, antioxidant enzymes, DNA, metallothionein) once the environmental stressors or toxic chemicals have reached high concentrations in the environment. This review contains selected investigations of the last years from the numerous articles in the scientific literature on the subject of oxidative stress, explaining the methodology, the type of aquatic species used, the damage in important  biological molecules and the extent of environmental pollution affecting aquatic and marine organisms and ecosystems.