The synthesis of cylindrical silicon-core and ferroelectric oxide perovskite-shell nanowires and their response characteristics as individual three-terminal nanoscale electronic devices is reported. The co-axial nanowire geometry facilitates large ferroelectric field-effect modulation (>10(4)) of nanowire conductivity following sequential application and removal of an applied dc field. Source-drain current-voltage traces collected during sweeps of ferroelectric gate potential and switching of the component of shell outward and inward polarization provide direct evidence of ferroelectric coupling on nanowire channel conductance. Despite a very small (1:20) ferroelectric-to-semiconductor channel thickness ratio, an unexpectedly strong electrostatic coupling of ferroelectric polarization to channel conductance is observed because of the co-axial gate geometry and curvature-induced strain enhancement of ferroelectric polarization.