Environmental impact assessment is the process of identifying and evaluating the consequences of human actions on the environment and, when appropriate, mitigating those consequences. The paper deals with environmental impact assessment of the proposed Sereď – Hlohovec water work, and describes an endeavour at the design, management and conduction of impact assessment. The goal of impact assessment is to improve the decision-making process through which the project is planned, designed, and implemented. The water work will be placed in the Váh river inundation area, in the section beginning by the Kráľová water work impound (Sereď) and ending by the outlet canal of the Madunice power plant (Hlohovec). The entire construction has a line character and the individual objects are located ina 24-kliometer north-south line. The utilization and quantification of the extent depend on the technical variant of the water work, which is either the power canal variant or the river stage variant.