Semiconductive oxide glasses in the system V2O5-MnO-TeO2 were prepared, and the mechanism of d.c. conduction was studied. The Seebeck coefficient measurements at temperatures from 375-475 K indicated the glasses to be n-type semiconducting. The d.c. conductivity ranged from 5x10(-5) to 1.9x10(-6) S cm(-1) at 405 K for V2O5=60 mol% and MnO=0-20 mol%, and decreased with increasing MnO content. The conduction was confirmed to obey the adiabatic small polaron hopping model, and was due to mainly hopping between V-ions in the glasses. The polaron band width J was estimated to be J=0.10-0.20 eV. The electron-phonon interaction coefficient gamma(p) was very large (21-26). The hopping mobility evaluated as 2.3x10(-7)-2.7x10(-6) cm(2) V-1 s(-1) increased with increasing V2O5 content. The estimated carrier concentration was the order of 10(19) cm(-3). The principal factor determining conductivity was the polaron hopping mobility in these glasses.