The research analyzed the influence of pH and aeration of the above-sediment water on the amount of copper released from the contaminated bottom sediments from the Rybnik Reservoir. Leaching of copper from the bottom sediment in the non-aerated systems was the highest when pH reached 2.0-3.5. For the aerated systems, the range was from 2.0 to 4.5. A dependence of the amounts of leached water on the leaching time was also observed. Sulfides were a predominant form of copper occurrence in the bottom sediment (60%). The remaining forms were as follows: organically bound, carbonates > residual > adsorbed > exchangeable.