The purpose of this study was to assess the expression of the bcl-2 oncoprotein in meningiomas and to compare it with the phenotype, the Ki-67 proliferative index and the sex hormone receptor status of the tumors. The expression of the bcl-2 oncoprotein was studied by Western blotting and immunohistochemistry. A quantitative study of the Ki-67 proliferative index and the expression of estrogen and progesterone receptors was performed. Western blot detected the bcl-2 oncoprotein in nearly all meningiomas. Immunohistochemistry detected the oncogene in only 43.5% of the cases. Expression of bcl-2 was essentially by spindle cells of transitional and fibrous meningiomas expressing neural cell adhesion molecule. There was neither correlation between the expression of bcl-2 and Ki-67 proliferative index of meningiomas nor statistical concordance between the expression of bcl-2 oncoprotein by meningiomas and their sex hormone receptor protein status. Inhibition of apoptosis could be involved in the growth of meningiomas with a mesenchymal differentiation.