Magnetic chemically peculiar stars of the upper main sequence are slowly rotating early B to early F-type objects with elemental overabundances of several orders of magnitude compared to the Sun. The driving mechanism is diffusion in the calm stellar atmosphere intensified by the presence of a stable organized magnetic field. The binary fraction is vital to understanding the formation and evolution of these objects as well as possible operating angular momentum loss mechanisms. The available literature on the binary fraction is reviewed and a list of needed future working steps is presented.