The approximate energy bands for Cr, Mo and W metals are built up from the energy bands for the paramagnetic Cr metal, by taking into account the spin-orbit interaction. The effect of the spin-orbitinteraction to the paramagnetic susceptibilities for 3d, 4d and 5d b.c.c. transition metals and their alloys are investigated. The spin paramagnetic susceptibilities χs and the orbital paramagnetic susceptibilities χorb for 3d metals and their alloys are the largest, followed by those for 4d and 5d metals and their alloys in that order, and the mixed contribution due to the spin and orbital angular momentums, χso, is negligibly small. The calculated paramagnetic susceptibilities agree with the results of the experiments, by adopting the reasonable values of a molecular field coefficient. The method to analyze the paramagnetic susceptibilities for the alloys composed of 3d and 4d, 4d and 5d or 3d and 5d transition metals is suggested and the experimental results for V–Nb and Nb–Ta alloys are analyzed. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.