In addition to their usual diet, 17 lactovegetarian college students consumed 400 kcal of test foods per day containing one extra-large egg for three weeks and similar isocaloric eggless foods for an additional three weeks in a randomised double-blind crossover trial. Ingestion of the egg increased dietary cholesterol from 97 to 418 mg per day. Mean plasma low density lipoprotein (LDL) cholesterol was 12% higher (p = 0.005) and mean plasma apolipoprotein B was 9% higher (p = 0.007) when eggs were being consumed than during the eggless period. Mean plasma high density lipoprotein cholesterol, apolipoproteins A-I and A-II, very low density lipoprotein cholesterol, and total triglycerides did not change significantly. Thus, ingestion of egg seems selectively to raise cholesterol and protein in LDL particles in the plasma of free-living normal people. Plasma LDL may be more sensitive to cholesterol at low intakes than at moderate to high intakes.