This paper presents the results of microbiological research on the water of the River Vistula between Wyszogród and Toruń, as regards the total number of planktonic bacteria (TNB), the number of heterotrophic bacteria: psychrophilic (TVC 20oC) and mesophilic (TVC 37oC), the occurrence of anaerobic spore-forming bacteria, and the number of coliform bacteria, faecal coliforms and faecal streptococci. The value of the Korsh coefficient and the titre of coli indicate that the waters of the Lower Vistula on the Wyszogród – Toruń section are moderately polluted and in the majority of cases may be classified as class III purity, with the exception of sections of the river near Płock and Toruń, which are unclassified. The values of the FC/FS ratio indicate the predominance of faecal contamination of human origin.