The talk will summarize present state understanding of conditions in different Martian ecological niches and their analogs on Earth. Speaking about the search for terrestrial-like life based on H₂O, Mars may be divided on five ecological niches according to presence and state of water: permanent polar caps, dry regolith, subpermafrost aquifers, cryopegs and ice containing regolith. Basic limiting factors for the search of life in this econiches are: absence of water (dry regolith), depth of burial (cryopegs and subpermafrost aquifers), age (ice containing permafrost and polar caps). High priority targets for the search of life on Mars are represented by permanently frozen deposits of young polar volcanoes and ice in pingos. During volcanic eruptions and ground water seepage microorganisms from subpermafrost aquifers could propagate to the surface and survive in permafrost or ice for million years, as it is known to happen on Earth.