  We discuss the possibility of screening the atmosphere of exomoons for
habitability. We concentrate on Earth-like satellites of extrasolar giant
planets (EGP) which orbit in the Habitable Zone of their host stars. The
detectability of exomoons for EGP in the Habitable Zone has recently been shown
to be feasible with the Kepler Mission or equivalent photometry using transit
duration observations. Using the Earth itself as a proxy we show the potential
and limits of spectroscopy to detect biomarkers on an Earth-like exomoon and
discuss effects of tidal locking for such potential habitats. Transmission
spectroscopy of exomoons is a unique potential tool to screen them for
habitability in the near future.
