  ISGRI, the IBIS low energy camera (15 keV - 1 MeV) on board INTEGRAL, is the
first large CdTe gamma-ray imager in orbit. We present here an overview of the
ISGRI in-flight calibrations performed during the first months after launch. We
discuss the stability of the camera as well as the CdTe pixels response under
cosmic radiation. The energy calibra tions were done using lead and tungsten
fluorescence lines and the $\mathrm{^{22}Na}$ calibration unit. Thermal effects
and charge correction algorithm are discussed, and the resulting energy
resolution is presented. The ISGRI background spatial and spectral
non-uniformity is also described, and some image correction results are
presented.
