A backlight unit using a microwave plasma ultraviolet lamp as a light source and a liquid crystal display including the backlight unit. The backlight unit for a liquid crystal display comprises a tube filled with discharge gas, a cavity resonator in which one end of the tube is inserted, a magnetron for generating microwaves and supplying the generated microwaves to the cavity resonator, a magnetron driver for driving the magnetron, and a phosphor layer for converting ultraviolet light generated in the tube into visible light.