A new high-current H − injector has been installed at LAMPF for the proton storage ring. The injector is equipped with a multicusp surface-production H − ion source that was developed at LAMPF. The ion source is capable of long-term operation at 20 mA of H − current at 10% duty factor and with normalized beam emittance of 0.08 cm mrad (95% beam fraction). Details of the development program, the injector design, and initial operating experience are discussed. Included in the discussion is a comparison of intensity and emittance measurements of the same H − beam at 100 keV and 750 keV.