Observations are reported on the effect of specimen motion upon the neutron diffraction pattern of iron. Specimen speeds of 120 m/sec combined with a neutron speed of 3310 m/sec are found to produce easily measured angular shifts, integrated intensity changes, neutron wavelength alteration, and peak width changes all of which are dependent upon the direction of motion relative to the scattering vector. The effects can be conveniently interpreted with the reciprocal lattice construction and the calculated changes with motion agree satisfactorily with the observations.