The preparation and characterization of a novel rare-gas-containing compound HXeNCO in solid Xe is described. HXeNCO is formed in two ways. Photolysis of HNCO at 193 nm in solid Xe directly produces HXeNCO providing the first experimental evidence of direct photoinduced formation of a HXY-type rare-gas compound (X = Xe, Kr; Y is an electronegative fragment), which can be attributed to relatively high photostability of HXeNCO. This finding particularly shows that the HXY compounds can be intermediates in the photolysis of HY in the presence of X. The amount of HXeNCO produced initially in photolysis of HNCO remains small because HXeNCO decomposes under irradiation. More efficient production of HXeNCO is achieved in the thermal reaction H + Xe + NCO --> HXeNCO after photolysis of HNCO. HXeNCO has two strong IR absorptions: the asymmetric NCO stretch at 2148.3 cm(-1) and the Xe-H stretch at 1788.1 cm(-1). The assignment is supported by the deuteration experiments and the ab initio calculations. HXeNCO decomposes at 405 nm irradiation producing HNCO and (H + NCO).