The aim of this study was to determine spatial distribution of mercury in floodplain soils of the middle Warta river with special regard to the polluting influence of the city of Poznań (capital of the Wielkopolska District) and high water levels and floods. Total mercury concentration was determined in samples collected from eleven sampling sites located above, below and in the area of Poznań agglomeration. From each site three soil samples were collected at distances of 1, 10 and 50 meters from riverside. The method used for the determinations was cold vapour atomic fluorescence spectrometry (CV–AFS). The results of the study have shown that mercury distribution in the samples of floodplain soil of Warta river was relatively uniform. However, higher mercury concentrations were found in the floodplain soils collected below of Poznań (median 300 ng g^-1, range 75–884), lower in soil samples above of Poznań (228 ng g^-1, range 54–754) and from the city area (183 ng g^-1, range 72–303).