In order to examine the influence of a low-fat diet on iron status, we carried out a study which involved 410 out-patients with hyperlipidaemia, i.e. 256 men and 154 women. Serum iron was positively correlated with protein intake (p = 0.11; p < 0.05) and transferrin saturation was inversely correlated with fat intake (p = - 0.12; p < 0.05). A positive iron balance (serum iron > 27 mumol/l and transferrin saturation > 45%) was found in 1.6% of the male subjects, a frequency which could be explained by the presence of the hemochromatosis genes. A negative iron balance (serum iron < 10 mumol/l and tranferrin saturation < 15%) was found in 13.7% for women aged 21-49 yr, 3.7% for women aged 50-77 yr and 3.5% for men aged 21-77 yr. We found no association between low-fat diet and iron deficiency. Men with iron deficiency had 12% decrease in total calorie intake compared to the Recommended Dietary Allowance. Our results do not provide evidence that hypolipidemic diet is associated with a high frequency of iron deficiency.