  A new high-quality set of orbital parameters for the O-type spectroscopic
binary HD93205 has been obtained combining echelle and coude CCD observations.
The radial velocity orbits derived from the HeII 4686 A (primary component) and
HeI 4471 A (secondary component) absorption lines yield semiamplitudes of 133
+/- 2 and 314 +/- 2 km/s for each binary component, resulting in minimum masses
of 31 and 13 Msol (q = 0.42). We also confirm for the binary components the
spectral classification of O3V+O8V previously assigned. Assuming for the O8V
component a ``normal'' mass of 22 - 25 Msol we would derive for the primary O3V
a mass of ``only'' 52 - 60 Msol and an inclination of about 55 degrees for the
orbital plane. We have also determined for the first time a period of apsidal
motion for this system, namely 185 +/- 16 years using all available radial
velocity data-sets of HD 93205 (from 1975 to 1999). Phase-locked variations of
the X-ray emission of HD 93205 consisting of a rise of the observed X-ray flux
near periastron passage, are also discussed.
