Tumor-associated proteins are studied immunohistochemically in 86 medulloblastomas (MB). Three main variants of their coexpression (70% of all cases studied) are distinguished. The 1st variant (24 cases): expression of Rb and nm23 proteins and the lack of tenascin expression. The 2nd variant (25 cases): tenascin expression and lack of Rb and nm23 expression. The 3rd variant (12 cases): the expression of tenascin, Rb, p53 and/or bc12. Tenascin-positive MB much more frequently expressed oncoproteins p53, bc12, c-erb B-2 and p30/32, and had higher indices of "growth fraction". Tenascin immunoreactivity and that of other oncoproteins prevailed in MB with desmoplasia and in tumors with immunohistochemical features of neuronal differentiation.