We carried out a probabilistic analysis of the dynamics of flood risks for the selected area of the Oder River basin. The authors based their risk dynamics assessment on results from the distributions of the maximum values for a selected hydrological characteristic, namely flow rate. On the basis of the daily flow data from 1994-2013 collected at a hydrological station on the Oder River in the town of Malczyce, 30-day flow maxima were selected individually for four five-year periods. Then, a probabilistic model of maximal flow was estimated on the basis of these peaks for each five-year period. The resulting models were used to estimate flood risks and analyze the dynamics of the studied area.