The selenium (Se) intake and status of 82 very low birth weight infants (birth weight 1110 +/- 286 g, gestational age 29.2 +/- 3 wk, mean +/- SD) was assessed at 36.3 +/- 3 postconceptional wk, at 40.1 +/- 4 wk (hospital discharge), and at 3, 6, 9, and 12 +/- 0.75 mo corrected for gestational age. Infants were fed formula containing 0.13 mumol/L (10 micrograms/L) Se. Se-dependent glutathione peroxidase activity in red blood cells declined corresponding to low Se intakes (micrograms/kd/d) for the first 6 mo. With increased consumption of solid foods, intakes of dietary Se and Se-dependent glutathione peroxidase activity increased at 9 mo, suggesting that the earlier supply of Se was suboptimal. Se-dependent glutathione peroxidase activity and intakes of Se were lower in males than in females (p < 0.05). We suggest that infant formulas should probably contain 0.26-0.33 mumol/L (20-25 micrograms/L) Se, particularly those formulas consumed by very low birth weight infants.