The crystal structure of bretylium tosylate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Bretylium tosylate crystallizes in space group C2/c (#15) with a = 32.6238(4), b = 12.40353(14), c = 9.93864(12) Å, β = 101.4676(10), V = 3941.39(5) Å3, and Z = 8. The sample exhibited visible decomposition in the X-ray beam. The unusual displacement ellipsoid of the Br atom probably indicates that the decomposition in the beam involves the Br atom. The crystal structure can be viewed as layered parallel to the bc plane. The layers are double, the center consisting of the cation/anion polar interactions and the outer surface of the double layers consists of hydrocarbon interactions. In the absence of normal hydrogen bond donors, the only hydrogen bonds in the bretylium tosylate structure are C–H…O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.