An LED bulb with a down-reflecting optic is disclosed. Embodiments of the present invention can provide for an omnidirectional intensity distribution in the vertical plane for a vertically oriented solid-state lamp. In example embodiments, an optically transmissive enclosure is installed on the driver base. A plurality of LEDs are mounted on a mounting surface of the driver base, and an optical arrangement is disposed at least partially in an optical path from the plurality of LEDs to a central area of the optically transmissive enclosure to down-reflect at least some light from the plurality of LEDs. The optical arrangement can include a TIR optic with a spline-driving surface to down-reflect the at least some light from the plurality of LEDs, or a substantially flat mirror. Either may include a central aperture, and the optical arrangement may include a diffuser or diffusive areas.