In order to meet the requirements of modern electronic devices, such as high power factor, low current harmonics, high efficiency and low cost, a single-switch high-power-factor electronic ballast for fluorescent lamps is proposed in this paper. The electronic ballast will benefit from simpler configuration, fewer components, low current stress and therefore high efficiency and low cost. The proposed ballast circuit is composed of the integration of a buck-boost converter and a class-E resonant inverter. The electronic ballast can achieve unity power factor by operating the buck-boost converter at discontinuous current mode (DCM). With carefully designed circuit parameters, the active power switches can be operated at zero-current switching, leading to a high efficiency.