The purpose of this study was to evaluate the differences that occur within the plasma compartment of normolipidemic men, classified on the basis of their response to prolonged consumption of additional dietary cholesterol. Using a crossover design, 40 men aged 18-57 y were randomly allocated to an egg (640 mg/d additional dietary cholesterol) or placebo group (0 mg/d additional dietary cholesterol), for two 30-d periods, which were separated by a 3-wk washout period. Subjects were classified as hypo- [increase in plasma total cholesterol (TC) of <0.05 mmol/L for each additional 100 mg of dietary cholesterol consumed] or hyperresponders (increase in TC of > or =0.06 mmol/L for each additional 100 mg of dietary cholesterol consumed) on the basis of their plasma reaction to the additional dietary cholesterol provided. Male hyporesponders did not experience an increase in LDL cholesterol (LDL-C) or HDL cholesterol (HDL-C) during the egg period, whereas both lipoproteins were significantly (P < 0.0001 and P < 0.05, respectively) elevated in hyperresponders. Although the LDL/HDL ratio was increased in male hyperresponders after the high cholesterol period, the mean increase experienced by this population was still within National Cholesterol Education Program guidelines. Furthermore, male hyperresponders had higher lecithin cholesterol acyltransferase (P < 0.05) and cholesteryl ester transfer protein (P < 0.05) activities during the egg period, which suggests an increase in reverse cholesterol transport. These data suggest that additional dietary cholesterol does not increase the risk of developing an atherogenic lipoprotein profile in healthy men, regardless of their response classification.