  The observations of all three COBE instruments are examined for the effects
of dark matter. The anisotropy measured by the DMR, and especially the
degree-scale ground- and balloon-based experiments, is only compatible with
large-scale structure formation by gravity if the Universe is dominated by
non-baryonic dark matter. The FIRAS instrument measures the total power
radiated by cold dust, and thus places tight limits on the absorption of
starlight by very cold gas and dust in the outer Milky Way. The DIRBE
instrument measures the infrared background, and will place tight limits on the
emission by low mass stars in the Galactic halo.
