  The modification of the width of the rho meson due to in-medium decays and
collisions is evaluated. In high temperature and/or high density hadronic
matter, the collision width is much larger than the one-loop decay width. The
large width of the $\rho$ meson in matter seems to be consistent with some
current interpretations of the $e^+ e^-$ mass spectra measured at the CERN/SPS.
