  A new type of high-energy binary system has been revealed by the INTEGRAL
satellite. These sources are being unveiled by means of multi-wavelength
optical, near- and mid-infrared observations. Among these sources, two distinct
classes are appearing: the first one is constituted of intrinsically obscured
high-energy sources, of which IGR J16318-4848 seems to be the most extreme
example. The second one is populated by the so-called supergiant fast X-ray
transients, with IGR J17544-2619 being the archetype. We report here on
multi-wavelength optical to mid-infrared observations of a sample constituted
of 21 INTEGRAL sources. We show that in the case of the obscured sources our
observations suggest the presence of absorbing material (dust and/or cold gas)
enshrouding the whole binary system. We finally discuss the nature of these two
different types of sources, in the context of high energy binary systems.
