This report describes photoluminescence (PL) properties of PbTe/CdTe single quantum wells grown on GaAs(100) substrates by molecular beam epitaxy. Despite the differences in crystal structure and band ordering between PbTe and CdTe, an intense emission in the mid-infrared region was observed for the first time. The energy of the emission peak showed blue shift with decreasing well width and had a positive dependence on temperature in agreement with that of bulk PbTe, indicating that the emission resulted from electron hole recombination in a type I quantum well. Too much thermal stress, however, was found to deteriorate the PL properties, and the analysis on the peak energy dependence on temperature revealed an important effect of the thermal expansion difference between the constituent materials. (C) 2003 Elsevier B.V. All rights reserved.