Serum and corpuscular nickel and zinc concentrations in 30 chronic hemodialysis patients were examined. Serum nickel and zinc levels before dialysis were 0.22 +/- 0.03 microgram/dl (normal value: 0.56 +/- 0.08 microgram/dl) and 70.0 +/- 13.4 micrograms/dl (normal value: 96 +/- 8 micrograms/dl) low, respectively. However, corpuscular nickel and zinc levels before dialysis were high: 1.25 +/- 0.24 microgram/dl (normal value: 0.88 +/- 0.17 microgram/dl) and 1,299 +/- 146 micrograms/dl (normal value: 1,120 +/- 80 micrograms/dl). Serum zinc levels significantly increased after dialysis, but serum nickel concentrations did not significantly increase during dialysis. Corpuscular nickel and zinc concentrations did not significantly change during dialysis.