The presence of Salmonella and its relationship with indicators of faecal pollution was investigated in aquatic habitats. The highest frequency was obtained in rivers (58.7% of samples) followed by freshwater reservoirs (14.8%) and sea water (5.9%). The sporadic presence of Salmonella ( 6 30%) on beaches with low concentrations of faecal streptococci (mean 25 CFU (100 ml) 3I ) may represent a potential risk for bathers in agreement with data found in previous epidemiological studies. Absence of Salmonella was observed only on beaches with very low densities (CFU (100 ml) 3I ) of indicator organisms (25 total coliforms, 13 faecal coliforms and 17 faecal streptococci). z 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V.