This paper outlines research on the use of lignite washery sludge as the amendment for reclamation of lignite mine soil and stimulating poplar trees growth. Sludge is characterized by high total C content ($34%) and high C/N ratio (68:1). The sludge was introduced by ploughing in, down to 20-25 cm depth, in the quantities: 0, 28, 56 and 112 t ha À1 . We have established that the N percentage in poplar leaves decreases with introducing increasing quantities of sludge into the mine soil. On the other hand, the content of B and Cd increased with increasing sludge quantities. The As content in poplar leaves did not correlate with the applied quantities of sludge, but it did with the P, Fe and Zn content in the leaves. Introducing this sludge can have a positive effect on annual tree trunk increment, but only in the subsequent phases of growth. In the first few years an increase of total C content by introducing lignite washery sludge is not sufficient to provide the conditions for faster growth of trees.