The effects of S and N deposition on leaching of ions from soil, tree growth and chemical content of needles have been studied in a lysimeter experiment. Lysimeters with Scots pine saplings were treated with artificial acid rain, in which pH was adjusted with H 2SO 4. Additionally, the lysimeters were treated with NH 4NO 3, in doses corresponding to 0, 30 and 90 kg N/ha yr. After 5 yrs of treatment, the following effects were the most pronounced: enhanced S input increased the leaching of SO 4 2−, H +, Na +, Mg 2+, Ca 2+, Al, Mn 2+ and NH 4 + from soil. Even though a large proportion of the SO 4 2− added was sorbed in soil, SO 4 2− was mobile in the soil investigated. In average for all treatments, 26% of the NO 3 − added to the lysimeters was leached. The leaching of NH 4 + was less than 5% of the amount of NH 4 + applied. When treated with 90 kg N/ha yr, the leaching of both NO 3 − and NH 4 + increased significantly, but in percent of input, the leaching of N compounds decreased. Since most of the N added was retained within the soil/plant system, the system can hardly be said to be ‘N-saturated’. Except for increased Al, H + and NH 4 + leaching, no clear relationships between the enhanced N input and leaching of other cations from soil were observed. Increased N deposition significantly increased the height of the Scots pine saplings. The height increment was accompanied by reductions in the contents of Mg, K and P in the needles. When considering the ratios Mg N , K N , Ca N , P N and Mn N in the needles, reductions were observed with increasing N input. These reductions may be caused by dilution due to the increased growth promoted by the N application, but they could also be signals of insufficient nutrient availability in the soil. In combination with N input, enhanced S input slightly increased the concentration of NH 4 + in the leachate. Combined S and N input increased the content of P in the needles relative to the lysimeters receiving high doses of N, but no S. A decreased needle Mg content following the increased N input was probably strengthened by increased Mg 2+ leaching due to increased S input.