  The Chandra ACIS Survey of M33 (ChASeM33) has acquired 7 fields of ACIS data
covering M33 with 200 ks of exposure in each field. A catalog from the first 10
months of data, along with archival Chandra observations dating back to the
year 2000, is currently available. We have searched these data for transient
sources that are measured to have a 0.35-8.0 keV unabsorbed luminosity of at
least 4$\times10^{35}$ erg s$^{-1}$ in one epoch and are not detected in
another epoch. This set of the survey data has yielded seven such sources,
including one previously-known supersoft source. We analyzed XMM-Newton data
from the archive distributed over the years 2000 to 2003 to search for
recurrent outbursts and to get a spectrum for the supersoft transient. We find
only one recurrent transient in our sample. The X-ray spectra, light curves,
and optical counterpart candidates of two of the other sources suggest that
they are high-mass X-ray binaries. Archival Spitzer photometry and high X-ray
absorption suggest that one of the sources is a highly variable background
active galactic nucleus. The other three sources are more difficult to
classify. The bright transient population of M33 appears to contain a large
fraction of high-mass X-ray binaries compared with the transient populations of
M31 and the Galaxy, reflecting the later morphology of M33.
