The structural evolution of recently characterized sodium nitride Na 3 N as a function of pressure was investigated at room temperature by the angle-dispersive powder x-ray diffraction in a diamond-anvil cell up to 36 GPa. The rather open cubic anti-ReO 3 -type structure stable at ambient pressure is followed by a series of four high-pressure modifications. Along the route, the coordination number for the nitride anion increases from 6 in Na 3 N-I to 8 in hexagonal Li 3 N-type Na 3 N-II, 9 in orthorhombic anti-YF 3 -type Na 3 N-III, 11 in hexagonal Cu 3 P-type Na 3 N-IV, and finally 14 in cubic Li 3 Bi-type Na 3 N-V structures. The experimental data are compared to the results of total-energy calculations and are discussed with regard to the structural details of the five phases and their equations of state.