Nutrition is of critical importance to very low birth weight (VLBW) survival. Intravenous (iv) lipid tolerance has been studied using a soybean or safflower-based lipid emulsion. We studied lipid levels in a group of VLBW infants on both intravenous lipids (soybean-safflower emulsion) and on enteral feedings (24 cal/oz premature formula). Levels were obtained on 1, 2, and 3 g/kg/day of iv lipid and after 3 and 10 days of feeding. Triglyceride (TG) and free fatty acid (FFA) proved the most sensitive indicator of both iv and enteral tolerance. The higher the lipid dose, the more likely there would be elevated lipid levels, especially FFA. Mean lipid levels for the group of enteral-fed infants were normal. Comparison of lipid levels on iv to those on enteral feedings showed significant differences in trough iv levels of TG compared to preprandial TG. FFAs tended to be significantly higher on iv feedings. Monitoring lipid levels on iv and enteral feedings is appropriate to document tolerance.