Two spectrophotometric methods for the assay of serum iron without deproteinisation are compared: 1. Liberation of iron by a detergent (Teepol SHELL), reduction by dithionite, chelation by bathopehanthroline disulfonate; 2. Liberation of iron by 6 mol/l guanidine, reduction by ascorbic acid, chelation by 3-(2-pyridyl)-5,6-bis-(4-phenyl sulfonic acid)-1,2,4-triaxine (Ferrozine).