A magnetically actuated valve (10) which includes a one-piece valve body (16, 80), a linearly translatable poppet (24, 98) for selectively blocking an aperture in the valve body, a magnetically operable rotor (28), a magnetic collar (38) or electromagnetic coil (42) external to the valve body for inducing rotation of the rotor, and a screw and nut arrangement (48) for converting rotational motion of the rotor (28) into linear motion of the poppet (24, 98).