  We present mid-infrared spectrophotometric observations of SS433 with
ISOPHOT. The HeI+HeII lines in both spectra of SS433 and of the Wolf-Rayet star
WR147, a wind-colliding WN8+BO5 binary system, closely match. The 2.5-12 micron
continuum radiation is due to an expanding wind free-free emission in an
intermediate case between optically thick and optically thin regimes. The
inferred mass loss rate evaluation gives ~10^{-4} Msun/yr. Our results are
consistent with a Wolf-Rayet-like companion to the compact object in SS433. A
similar study for Cygnus X-3 confirms the Wolf-Rayet-like nature of its
companion, although with a later WN type than previously suggested.
