Field-effect transistors (FETs) having nanowire channels are provided. In one aspect, a FET is provided. The FET comprises a substrate having a silicon-on-insulator (SOI) layer which is divided into at least two sections electrically isolated from one another, one section included in a source region and the other section included in a drain region; a channel region connecting the source region and the drain region and including at least one nanowire; an epitaxial semiconductor material, grown from the SOI layer, covering the nanowire and attaching the nanowire to each section of the SOI layer; and a gate over the channel region.