ABSTRACT: The Little Danube (Malý Dunaj River) is a lowland slow but steady stream flowing through the Bratislava, Trnava and Nitra regions. It is the left-hand inland arm of the European Danube. It starts in Bratislava, meanders through the forests of the Danubian Lowland and flows into Váh near Kolárovo. The surface water of the Little Danube is primarily a source of irrigation water and its energy is used by hydroelectric power plants. The long-term changes of surface water quality for the period 2009 – 2016 are evaluated, too. Thanks to the knowledge obtained this work suggests a monitoring of the Little Danube. Despite the observed elevated concentrations of indicators in surface water of the Little Danube, it can be stated that the quality of surface water along the whole river run of the Little Danube was acceptable. It’s deterioration was particularly evident in the upper and middle part of the flow. In long term changes for the period 2009 – 2016 the improvement of the surface water quality has been observed. This paper presents the results of the Thesis (Jamrišková, 2016), was aim to determine the characteristics of the Little Danube surface water quality with regard to its chemical composition and microbial profile, an assessment of water quality in accordance with the current legislation, the influence of the Čierna voda River and Klátovské rameno River on the quality of the Little Danube surface water.