  Band structure calculations within the local spin-density approximation are
presented in order to investigate the electronic and magnetic properties of the
zigzag spin-chain compound In$_2$VO$_5$. The essential structural feature of
the system is a double chain of VO$_6$-octahedra, which leads to competing
intrachain and interchain magnetic couplings. Frustration of the spin-chains is
expected for the proposed antiferromagnetic ordering at low temperatures.
However, the band calculations show that the experimental room temperature
crystal structure is incompatible with antiferromagnetism. Both the intrachain
and interchain coupling is found to be ferromagnetic.
