Because carnitine is contained primarily in meats and dairy products, vegetarian diets provide a model for assessing the impact of prolonged low carnitine intake on carnitine status. Plasma carnitine concentrations and urinary carnitine excretion were measured in adults and children consuming a strict vegetarian, lactoovovegetarian, or mixed diet. In adults plasma carnitine concentration and urinary carnitine excretion of strict vegetarians and lactoovovegetarians were significantly lower than those in the mixed-diet group but were not different from each other. In children significant differences were found between all three diet groups for both plasma carnitine concentration and urinary carnitine excretion. The differences in plasma carnitine concentrations were greater in children than in adults, possibly reflecting the effects of growth and tissue deposition. Small differences between diet groups in adults do not suggest a nutritionally significant difference in carnitine status. Whether vegetarian children are at greater risk for overt deficiency is not answered.