Accurate frequency-dependent hyperpolarizabilities which incorporate the effects of electron correlation have been calculated for neon, argon, and krypton. Specifically, these values are derived from a previous "best estimate" static value based on coupled-cluster calculations, and use of a second-order perturbation theory frequency-dependent correction. The values for γK(-ω;ω,0,0) and γ∥(- 2ω;ω,ω,0) are compared with experiments for the d.c. Kerr effect and second harmonic generation, respectively. No negative dispersion is observed for either of these processes for neon, argon, and krypton. In particular, the second harmonic generation values for neon show a positive dispersion effect which is in agreement with other recent theoretical calculations and in line with recent measurements. This study demonstrates that it is possible to achieve quantitative accuracy for the frequency-dependent hyperpolarizabilities of dilute gas-phase many-electron systems. © 1992 American Institute of Physics.