Male Wistar rats were given nickel (II) chloride (NiCl2 · 6 H2O) with drinking water (300 or 1200 ppm Ni for 90 days). Urine volume and nickel, zinc, copper, calcium and inorganic phosphorus were measured in 24 h urine after 45 and 90 days of exposure. The results demonstrate that relatively low–level oral ex-posure (300 ppm Ni) induces an increase of urinary Ni excretion (p < 0.001), but no significant changes in other elements. The higher Ni dose (1200 ppm) caused elevation of this metal in urine (p < 0.001), as well as significant changes of urinary volume, and zinc, copper and inorganic phosphorus concentration.