Hypertriglyceridemia and fatty livers have been observed in pups of Fe-deficient rats. Lowered tissue carnitine level is proposed as a mechanism responsible for altered lipid metabolism. Two hydroxylases involved in carnitine synthesis have been shown to require Fe in vitro. To determine if dietary Fe deficiency reduces tissue carnitine levels, two groups of 12 rats were fed 6 ppm Fe (-Fe) or 250 ppm Fe (+Fe) ad libitum from d 1 gestation to d 16 lactation. Feeding -Fe diets to dams resulted in 15% lower hemoglobin levels in pups on d 2 (P less than 0.02) and 50% lower levels on d 16 (P less than 0.001). Total carnitine level (nanomoles/milligram noncollagen protein) and triacylglycerol were assayed in pup tissues on d 2 and 16. While tissue carnitine and triacyglycerol was similar on d 2, d 16 liver carnitine was lower (P less than 0.001), triacylglycerol was eightfold higher in -Fe pups than in controls. Fe deficiency did not alter either carnitine concentration in milk on d 2 or 16 or the concentration of amino acid precursors of carnitine in milk on d 16. Decreased carnitine levels in the -Fe rat pup are contribute to triacylglycerol accumulation in liver.