The aim of this observational study was to biochemically characterize the anaemia in GCA (giant cell arteritis) and PMR (polymyalgia rheumatica) patients. Values for mean corpuscular volume, mean corpuscular hemoglobin and soluble transferrin receptor were normal, whereas serum iron and total iron binding capacity (TIBC) were subnormal, and mean ferritin was above the upper reference limit. Iron-restricted erythropoiesis (IRE), defined as a bone marrow smear staining positive for iron in combination with transferrin saturation less than 20%, was present in all patients. All patients exhibited clinical and biochemical signs of active inflammation with elevated C-reactive protein and an increased erythrocyte sedimentation rate.