Over the past few years molecular biology techniques have revolutionized ecological research. The availability of simple and inexpensive ways to genetically characterize individuals and species has allowed us to quantify genetic diversity, track the movement of individuals, and characterize new species. One of these technologies is DNA microarray which has progressed rapidly in the hands of biological researchers for assessing gene expression analysis. It can provide a global view of how organisms respond to stressors (chemical pollutants, ultraviolet light, temperature changes, etc.) and has a great potential role as molecular biomarkers to anticipate the harmful effects of stressors in the aquatic ecosystem. The panel will meet the need in thoroughly explaining the role of molecular biology applied to environmental studies, and especially taking on board future perspectives in this field. The session will be divided into three parts: Molecular Biology and its Environmental Applications; Scientific Achievements in Molecular Ecotoxicology; and Looking into the Future.