The paper presents the results of analyses of nickel content in bottom sediments of four small dam reservoirs, as well as nickel content in water of tributaries to these reservoirs. The analyzed reservoirs, with capacities ranging from 34 to 3860 thousand m3, are located in southern Poland. Based on the results of analyses conducted over five years, i.e. in the periods 2005-2007 and 2012-2013, an attempt was made to determine the seasonal variation in the concentration of nickel in sediments along with the seasonal variation of nickel concentration in water flowing into these reservoirs. Additionally, an attempt was made to correlate the nickel concentration in water flowing into the reservoirs with nickel concentration of sediments. Also, nickel content in water and sediments was evaluated according to different criteria and standards. It was concluded that the concentration of nickel in sediments significantly exceeds the limits set for this element by the EQS. Significantly lower concentrations of nickel in water indicated that there is no risk of environmental contamination. The highest mean concentration of nickel in sediments was noted in samples collected in spring. On the other hand, the lowest mean Ni concentrations were observed in winter.