Persistent currents in multiwalled carbon nanotubes (MWNT's), driven by the magnetic field parallel to the tube axis are studied. The geometrical structure and possibility of the existence of MWNT's with shells in various chiral configurations are explored. The currents are calculated considering a possible Fermi energy shift by hole doping. The influence of self-inductance of different shells is taken into account. The optimal chiralities for the maximal current are found to be the armchair-only configuration (A) without doping and the zig-zag-chiral-chiral-zig-zag configuration ((B) and (C)) doped to EF =˛ g (g = 3.033 eV is the hopping integral between graphene sites). The hole doped (B) configurations are shown to exhibit spontaneous currents in Kelvin temperatures. In the optimal diamagnetic configuration (C) a Meissner-type effect, i.e., partial flux expulsion, occurs. Carbon nanotubes (henceforth referred to as CN's ) can play a major role in the design of the next-generation nano- electronic and nanoelectromechanical devices due to their novel mechanical and electronic properties. Among many other fascinating features, 1 carbon nanotubes have a topol- ogy which makes them particularly fit to investigate the phe- nomenon of persistent currents in the presence of static mag- netic field. In one of our earlier papers we studied persistent currents in pure and hole-doped single-wall nanotubes (SWNT's). 2 We have shown that the shape of the Fermi sur- face changes with the doping, which influences the ampli- tude and form of the persistent currents, and that the ampli- tudes of the currents and their associated magnetic moments were small. However, we know from the study of mesos- copic systems that they might increase with increasing num- ber of transverse channels. In this paper we investigate per- sistent currents in MWNTs, driven by an external magnetic field parallel to the tube axis. These currents are a superpo- sition of currents from different shells. Thus, the overall cur- rent can be significantly enhanced in those MWNTs where the currents from different shells add constructively, i.e., when they display the same paramagnetic or diamagnetic behaviour. However, different shells in MWNTs have in gen- eral different chiralities and the question arises whether we can find such favourable tube configurations. We have performed model calculations for several pos- sible configurations among which we found some which in- deed yielded large currents. We can then assume that the magnetic flux is the sum of the external flux and the flux coming from the currents themselves. We arrive at the self- consistent equation for the flux which can have spontaneous solutions, 3 i.e., a current running in the absence of the exter- nal field. Such spontaneous solutions appear when the cur- rents are paramagnetic. If the currents from different shells are diamagnetic, the MWNT can exhibit at least a partial flux expulsion. 5