We present updated results of the CP-PACS calculation of the light hadron spectrum in Nf = 2 full QCD. Simulations are made with an RG-improved gauge action and a tadpole-improved clover quark action for sea quark masses corresponding to mPS/mV ≈ 0.8-0.6 and the lattice spacing a = 0.22-0.09 fm. A comparison of the Nf = 2 QCD spectrum with new quenched results, obtained with the same improved action, shows clearly the existence of sea quark effects in vector meson masses. Results for light quark masses are also presented.