We report that the diamagnetism of as-grown YBa2Cu3O7-delta powders can be enhanced by treatment with RF-generated hydrogen plasma. The field-cooling susceptibility at 5 K is found to increase by up to 24%. The enhancement is reproducible for all five samples studied. The lattice parameter c decreases after hydrogenation. For a sample treated for the shortest period, its pinning potential, obtained from magnetic relaxation measurements, is reduced following H-treatment.