It was studied interband absorption of light in nanowires when a homogeneous electric field was directed along the axis of the nanostructure. Calculations of the absorption coefficient of a weak electromagnetic wave were carried out using the Kubo formula. The coefficient of interband absorption of light of frequency and polarization at , taking into account the scattering of carriers by long-wave acoustic oscillations during optical transitions between the lowest states of the valence band V and the conduction band , is determined by the relation:  – matrix element of the wave functions of electrons in the conduction band and in the valence band, – reduced mass of carriers; the parameter is related to the interaction of electrons (holes) with lattice vibrations, – the width of the forbidden band of the nanostructure.  In the electric field, the coefficient of light absorption for these optical transitions, without taking into account the interaction of the carriers with the dissipative subsystem, has the form: The figure shows the frequency dependence of the interband absorption of light (in relative units). The dotted line shows the frequency dependence of light absorption in the absence of an electric field. Curves 1, 2 describe the frequency dependence of the absorption coefficient at  As follows from the figure, with an increase in the intensity of a constant electric field, the oscillation dependence remains, but the distance between the maxima increases. We note that in the electric field, without taking into account the dissipation processes at , the absorption coefficient of light has no singularities, which, due to singularities in the density of energy states at the bottom of the size-quantized bands, arise at . The study was made of the effect of a homogeneous magnetic field directed perpendicular to the axis of the nanowire to be studied on the Franz-Keldysh effect. It is shown that the oscillation dependence of the interband absorption of light on frequency is conserved in a magnetic field. With increasing magnetic field strength, absorption maxima (Fig.) shift to high frequencies, what it is associated with an increase in the width of the forbidden band of nanowires, and the oscillation frequency increases.