Delipidation of liver homogenates, using an organic solvent system which does not denature proteins, increases measurable ferritin by 25-33%, compared to ferritin concentrations by standard heat supernatant assays. When applied to polyacrylamide gradient gels, lipid-associated ferritin does not enter the gel but after delipidation, this ferritin co-migrates with cytosolic ferritin and with purified liver ferritin. The biological significance of the association of ferritin with lipid has yet to be examined.