ABSTRACT: There are tens of artificial lakes in the Bratislava surroundings, so called gravel pits, used currently as natural swimming pools. By their origin they are related to the river Danube. The quality of the water is determined by various indicators, especially hydrochemical and microbiological ones. Significant indicator of faecal contamination is the presence of enterococci. Despite of the fact that there are only few differences in chemical content of the water in the Danube river and gravel pits, there are differences in the occurrence of enterococcal species; faecal enterococci (Enterococcus faecalis, E. faecium, E. durans, E. hirae) dominate in the river Danube, and only two non-faecal enterococcal species were found in the water of gravel pits: E. casseliflavus and E. seriolicida (identical genotype to Lactococcus garviae). The absence of the faecal enterococci in the gravel pits, even during the summer can be explained by relatively good self-cleaning ability of environment. Low content of nutritious sources expressed as BOD5, CODMn, CODCr and predacious pressure are not favourable for multiplication of enterococci in these environments. The river Danube enters the territory of Bratislava with higher content of enterococci compared to the gravel pits, what could be explained by higher presence of organic compounds.