  We investigate prospects for indirect detection of Kaluza--Klein dark matter,
focusing on the annihilation radiation of the first Kaluza--Klein excitation of
the Hypercharge gauge boson $B^{(1)}$ in the Galactic halo, in particular we
estimate neutrino, gamma-ray and synchrotron fluxes. Comparing the predicted
fluxes with observational data we are able to constrain the $B^{(1)}$ mass (and
therefore the compactification scale). The constraints depend on the specific
model adopted for the dark matter density profile. For a NFW profile the
analysis of synchrotron radiation puts a lower bound on the $B^{(1)}$ mass of
the order of $\simeq 300$ GeV.
