Low flows are an important component of the river regime. Their identification advances the knowledge about the formation of water resources in drought conditions. The analyses that we have carried out aimed to indicate the spatial structure of these flows. The study area was the Warta River catchment up to the water-gauge at Sieradz. The input research material consisted of series of daily discharge for 12 gauging stations located in this catchment, in the period of 1971–2000, made available by IMGW-PIB. At the first stage, periodic flows based on flow duration curve and annual minimum flows were determined. Their values have been converted into specific flows, which facilitated the conduct of comparative analyses. On the basis of the obtained results, the spatial variability of low flows in studied catchment was evaluated. The annual number of days with low flows was identified for all gauge sections. The dynamics and distribution of low flows in the multiannual time scale were evaluated. The analyses that have been carried out made it possible to identify the factors, which determine the structure of low flows. Research results have been illustrated with relevant maps and graphs.