The electronic states of a Kane-type cylindrical semiconductor quantum wire with and without magnetic field are theoretically investigated and compared with those of a quantum wire of the same size. The eigenstates and eigenvalues of the Kane's Hamiltonian are obtained. Calculations are performed for a hard-wall confinement potential and electronic states are obtained as a function of the magnetic field applied along the cylinder axis. We calculated the size dependence of the effective g-values in bare GaAs, InSb and InAs nanocrystals for electrons, light holes and spin-orbital splitting holes, respectively. It has been seen that the effective g-value of the electrons and light holes are decreased while that of the spin-orbit splitting holes is increased with the increasing of quantum wires radius. It is shown that the g-value for electrons in GaAs quantum wire changes sign as a function of quantum wire radius. (C) 2003 Elsevier Science B.V. All rights reserved.