Abstract: This paper focuses on the hydro-biological and hydro-chemical analysis of the Lazeshchyna River, one of the tributaries of the Tisza River from the cross-border territory within Rakhiv area of Ukraine’s Transcarpathian region. For this purpose, we used the results of route survey, hydro-biological and hydro-chemical analysis of the Lazeshchyna River surface water samples, which were collected forhydrochemical studies in 2017-2018. On the basis of water sampling we thoroughly analyzed the hydro-chemical water quality indicators of Lazeshchyna River according to the following groups of indicators: physic and chemical features, organic matter, water mineralization, major ions, nutrients, trace elements and specific pollutants. Hydrobiological studies were conducted in 2015-2016. Based on them, the water quality was assessed according to the Trent Biotic Index bioindication. The ratio of actual and maximum permissible concentration (MPC) hydro-chemical parameters are investigated, moreover we pointed out the seasonality in the ratio of water consumption and concentration of individual indicators. The study underlines the role of natural and anthropogenic factors for the Lazeshchyna River water quality.