  We examine the Inert Doublet Model in light of the discovery of a Higgs-like
boson with a mass of roughly 126 GeV at the LHC. We evaluate one-loop
corrections to the scalar masses and perform a numerical solution of the
one-loop renormalization group equations. Demanding vacuum stability,
perturbativity, and S-matrix unitarity, we compute the scale up to which the
model can be extrapolated. From this we derive constraints on the model
parameters in the presence of a 126 GeV Higgs boson. We perform an improved
calculation of the dark matter relic density with the Higgs mass fixed to the
measured value, taking into account the effects of three- and four-body final
states resulting from off-shell production of gauge bosons in dark matter
annihilation. Issues related to direct detection of dark matter are discussed,
in particular the role of hadronic uncertainties. The predictions for the
interesting decay mode h ->\gamma \gamma\ are presented for scenarios which
fulfill all model constraints, and we discuss how a potential enhancement of
this rate from the charged inert scalar is related to the properties of dark
matter in this model. We also apply LHC limits on Higgs boson decays to
invisible final states, which provide additional constraints on the mass of the
dark matter candidate. Finally, we propose three benchmark points that capture
different aspects of the relevant phenomenology.
