  Microquasars, X-ray binary systems that generate relativistic jets, were
discovered in our Galaxy in the last decade of the XXth century. Their name
indicates that they are manifestations of the same physics as quasars but on a
completely different scale. Parallel to this discovery, the EGRET instrument on
board of the Compton Gamma Ray Observatory detected 271 point like gamma-ray
sources 170 of which were not clearly identified with known objects. This
marked the beginning of gamma-ray source population studies in the Galaxy. We
present in this thesis models for gamma-ray production in microquasars with the
aim to propose them as possible parent populations for different groups of
EGRET unidentified sources. These models are developed for a variety of
scenarios taking into account several possible combinations, i.e. black holes
or neutron stars as the compact object, low mass or high mass stellar
companions, as well as leptonic or hadronic gamma-ray production processes. We
also show that the presented models for gamma-rays emitting microquasars can be
used to explain observations from well known sources that are detected in
energy ranges other than EGRET's. Finally, we include an alternative gamma-ray
producing situation that does not involve microquasars but a specific
unidentified EGRET source possibly linked to a magnetized accreting pulsar.
