The crystal structure of a new form of racemic reboxetine mesylate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Reboxetine mesylate crystallizes in space group P21/c (#14) with a = 14.3054(8), b = 18.0341(4), c = 16.7924(11) Å, β = 113.4470(17)°, V = 3,974.47(19) Å3, and Z = 8 at 298 K. The crystal structure consists of double columns of anions and cations along the a-axis. Strong N–H···O hydrogen bonds link the cations and anions into zig-zag chains along the a-axis. The powder pattern has been submitted to the International Centre for Diffraction Data (ICDD®) for inclusion in the Powder Diffraction File™ (PDF®).