In this work the design of a Ku-band reconfigurable phase shifter implemented in waveguide technology is presented. The reconfiguration capability of the device is achieved by the insertion of a pair of adjustable metallic posts. A prototype of this device has been manufactured using a 3D printing technique in order to show the proposed concept. The measured return loss and phase performances of this prototype are compared with the simulated full-wave response of the phase shifter. The proposed waveguide component shows a great application potential in the area of beam steering phased arrays implemented in waveguide technology, since the presented phase shifter is fully developed in waveguide, not requiring the additional transitions to planar structures usually needed to integrate lumped components.