The aim of the present paper was that of evaluating stains obtained with immunohistochemical methods performed in different laboratories. Serial sections obtained from the same paraffin block were used. Each laboratory was asked to use their respective current methods. The antibodies requested to be used were anti-oestrogen and progesterone receptors ad Ki-67, irrespective of the source. A great range of different results was obtained, when the several stains were evaluated, including the haematoxylin-eosin stain. It is suggested that a better harmonization among different laboratories is necessary.