The molecular electric dipole and quadrupole moments of HF have been calculated in Moller-Plesset perturbation theory through 20th order. From comparison with full configuration interaction results, the Moller-Plesset series is found to diverge for both properties. Within the Moller-Plesset series, only the second-order correction should be calculated. For higher accuracy, one should use coupled-cluster methods instead of proceeding to higher-order perturbation theory.