A chromium (Cr) balance study was conducted on a metabolic unit for 12 days in two normal males, ages 62 and 66, ingesting a nutritionally adequate, constant diet. Complete urine and stool collections were obtained daily. The diet, stool, and urine were analyzed for chromium by Zeeman atomic absorption spectrometry. On dietary Cr intakes of 36.9 and 36.7 micrograms/day, only a small fraction of the ingested Cr, 0.9 microgram and 0.5 microgram/day, was absorbed. Most of the dietary Cr, 36.0 micrograms and 36.2 micrograms/day, was excreted in the stool. Urinary Cr was constant from day to day with a mean of 0.30 microgram/day +/- 0.03 SD and 0.28 microgram/day +/- 0.05 SD. The Cr balances (apparent net retention) were positive, 0.6 and 0.2 microgram/day, indicating equilibrium. The average apparent net absorption of Cr for the two subjects was 1.8%.