Abstract.Cholesterol metabolism has been studied in a group of healthy males drawn from a New Guinea highland population whose plasma cholesterol concentration is low by Western standards and does not rise with age.Mean values from compartmental studies in six subjects were: pool A mass 289 mg/kg; production rate 1069 mg/day or 17.4 mg kg‐1day‐1. The average rate of endogenous synthesis measured by sterol balance in twelve men was 751 mg/day or 12.4 mg kg‐1day‐1. There was evidence of probable suppression of synthesis by about 500 mg/day when I g/day of egg yolk cholesterol was added to the diet of six subjects for 5 weeks. In the latter group, mean cholesterol absorption was 39% (390 mg/day) but the plasma cholesterol concentration did not rise, possibly reflecting compensatory reduction in synthesis.It is suggested that these results were unexceptional, except possibly for the failure of the plasma cholesterol concentration to rise when cholesterol was ingested, despite gross differences in diet and many other