The present disclosure relates to semiconductor structures and, more particularly, to an LDMOS device on FDSOI structures and methods of manufacture. The laterally double diffused semiconductor device includes a gate dielectric composed of a buried insulator material of a semiconductor on insulator (SOI) technology, a channel region composed of semiconductor material of the SOI technology and source/drain regions on a front side of the buried insulator material such that a gate is formed on a back side of the buried insulator material. The gate terminal can also be placed at a hybrid section used as a back-gate voltage to control the channel and the drift region of the device.