  We consider the O(N)-symmetric phi4 theory in two and three dimensions and
determine the nonperturbative mass renormalization needed to obtain the phi4
continuum theory. The required nonperturbative information is obtained by
resumming high-order perturbative series in the massive renormalization scheme,
taking into account their Borel summability and the known large-order behavior
of the coefficients. The results are in good agreement with those obtained in
lattice calculations.
