This discretionary time proposal results from our previous projects ABAUDRY.PROP_OD1 and ABAUDRY.CORE_OD2. We request 'exceptional' observing time on the ISO-LWS spectrometer in the direction of Orion-KL. In this source we wish to detect the same three IR lines of OD as in ABAUDRY.PROP_OD1 and ABAUDRY.CORE_OD2 . The OD radical, although predicted to be abundant by various chemical scenarios, has never been observed in space but will give important clues to D fractionation. The selected OD lines correspond to energy levels comparable to or lower than those involved in detected HDO and OH lines. From this, and because of the relatively high temperatures of the hot cores we infer that OD will be excited and will allow us to estimate its abundance relative to OH.