The problems connected with the collection of blood samples for chromium determination are shown with particular reference to the risk of chromium contamination which characterizes venous and capillary blood sampling. The use of various types of blood taking equipment (syringes with steel needles, platinum/ruthenium needles, intravenous catheters and lancets in steel of quarz) have been compared and analyzed (with references to the potential sources of chromium contamination during the collection and conservation of blood samples). By the use of the use of ETA-AAS "Zeema" procedure the references values of chromium in serum, read cells and whole blood in normal unexposed subjects living in a region of Northern Italy (Lombardy) have been determined.