This work comprises the results of a number of Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus sp. in water and bottom sediments in the Czarna Hancza River in the region of Suwalki and Wigry National Park from spring to autumn in 1996. All these microorganisms were found in smaller quantities in water, and in larger quantities in the bottom sediments in the Czarna Hancza River. Their number was generally higher than the number of faecal bacteria of Escherichia coli group both in water and bottom sediments in this river at site 1 (in Stary Brod above Suwatki) and at sites 7-10 (in Czerwony Folwark, Mackowa Ruda, Buda Ruska, Wysoki Most, to the east of Wigry Lake). Their number was close to or lower than the number of faecal bacteria of Escherichia coli group at the sites situated above and below the inflow of treated sewage from the Treatment Sewage Plant in Suwalki (2a and 2b sites), in Sobolewo (3 and 4 sites), in the region of the old river-bed of the Czarna Hancza River (5 site) and its mouth to Wigry Lake (6 site). There were fewer at the sites of sand deposits, more at the sites of clay-argillaceous deposits. In the research period they were more numerous in the second half of summer. The number of Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus sp. should be taken into account as well as the number of the indicators bacteria of a sanitary state (total coliforms, faecal coliforms and faecal streptococci) while estimating the usefulness of water in the Czarna Hancza River for recreation.