  HD 553 was discovered as an eclipsing binary by Hipparcos. Here, we present
the first radial velocity curve for this system. It is found that HD 553 is a
double-lined spectroscopic binary. Despite the large luminosity difference, the
two components of the system are of very simmilar mass. The primary, a
K0-giant, fills a large fraction of its Roche-lobe. The secondary is, despite
its very similar mass, still a late-type dwarf. The radial velocity curve
allows to constrain several stellar and system parameters.
