diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c
index 4653aacdcc8..8a4b27f55bf 100644
--- a/src/mesa/math/m_matrix.c
+++ b/src/mesa/math/m_matrix.c
@@ -1519,6 +1519,7 @@ _math_matrix_loadf( GLmatrix *mat, const GLfloat *m )
 void
 _math_matrix_ctr( GLmatrix *m )
 {
+   memset(m, 0, sizeof(*m));
    memcpy( m->m, Identity, sizeof(Identity) );
    memcpy( m->inv, Identity, sizeof(Identity) );
    m->type = MATRIX_IDENTITY;