  We report on the transport properties of nanostructures made from boron-doped
superconducting diamond. Starting from nanocrystalline superconducting
boron-doped diamond thin films, grown by Chemical Vapor Deposition, we pattern
by electron-beam lithography devices with dimensions in the nanometer range. We
show that even for such small devices, the superconducting properties of the
material are well preserved: for wires of width less than $100\, nm$, we
measure critical temperatures in the Kelvin range and critical field in the
Tesla range.
