  The energy spectra of X-ray binaries (XRBs) have been investigated during the
last few decades with many observatories in different energy bands and with
different energy resolutions. However, these studies are carried out in
selected states of XRBs like during outbursts, transitions, quiescent states,
and are always done in limited time windows of pointed observations. It is now
possible to investigate the long term averaged spectra of a large number of
X-ray binaries with the all sky monitor MAXI, which also has a broad energy
band. Here we present the average spectral behaviour of a few representative
XRBs. The long term averaged spectrum of Cyg X-1 is described by a sum of two
power-laws having $\Gamma_{1}$ ~ 2.8 and $\Gamma_{2}$ ~ 1.2, along with a multi
color disk blackbody having an inner disk temperature of 0.5 keV, GX 301-2 is
described by a power-law with a high energy cut-off at $E_{c}$ ~ 15 keV and a
blackbody component at 0.2 keV and that of Aql X-1 is described by a multi
color disk blackbody at 2 keV and a power-law of $\Gamma$ ~ 2.2. We have also
constructed the combined X-ray spectrum of the X-ray binaries in the Milky Way,
which can be compared to the XRBs spectra of other galaxies observed with
Chandra and XMM-Newton. These measurements are also relevant to investigate the
X-ray interaction with the ISM and its contribution to the ionising X-ray
background in the early universe.
