  We present X-ray observations of the ultraluminous infrared galaxy, UGC 5101,
thought to contain a buried active galactic nucleus (AGN) based on observations
in other wavebands. We detected an absorbed hard component at >3 keV, as well
as soft emission in the energy range 0.5-2 keV. The soft X-ray component,
possibly due to a modestly dust-obscured, extended starburst, has an
absorption-corrected 0.5-2 keV X-ray luminosity of LX(0.5-2 keV) = 1.2 * 10^41
ergs s^-1. The 0.5-2 keV X-ray to infrared luminosity ratio is a factor of 5
lower than typical values for a normal starburst, suggesting that this extended
starburst is unlikely to be energetically dominant in UGC 5101. The most
plausible origin of the absorbed hard component is the putative buried AGN. The
6.4 keV Fe K alpha emission line has a modest equivalent width (400 eV),
suggesting that this hard component is direct emission from the AGN, rather
than a scattered component. The absorption-corrected 2-10 keV X-ray luminosity
of the buried AGN was estimated to be LX(2-10 keV) = 5 * 10^42 ergs s^-1. The
intrinsic 2-10 keV X-ray luminosity and the 2-10 keV X-ray to infrared
luminosity ratio are both comparable to values measured for Mrk 463, a
Seyfert-2 galaxy of similar infrared luminosity.
