Intestinal copper absorption and blood measures of copper status were studied in healthy young men receiving varying intakes of ascorbic acid (AA) over 14 wk in a live-in nutrition suite. Copper absorption and retention were assessed by measuring absorption of a stable isotope of copper and total fecal copper during four AA intake periods: 2 wk x 65 mg AA/d, 4 wk x 5 mg/d, 3 wk x 605 mg/d and 4 wk x 5 mg/d. Measures of copper status were serum copper and serum ceruloplasmin determined by both enzymatic and immunochemical methods. Copper absorption, copper retention, total serum copper and the serum level of ceruloplasmin protein were not affected significantly by the changes in AA intake; however, the oxidase activity of serum ceruloplasmin was decreased an average of 21% during the high (605 mg/d) AA intake period. The results suggest that in adult men moderate supplemental intakes of AA reduce ceruloplasmin oxidase activity specifically but do not depress intestinal copper absorption or overall body copper status.