We studied the thermodn. properties of binary mixts. of noble gas atoms. Interat. interactions were specified by a 6-12 Lennard-Jones (LJ) potential. Starting from the global min. of the potential energy surfaces, the systems were heated by increasing the total energy until melting occurs. The melting was obsd. by monitoring the Lindemann factor. The effects of the relative sizes of A and B atoms and of the interaction strengths (A-A, A-B, and B-B) on the melting temp. of clusters contg. 50% of each component was analyzed by using const. energy (NVE) mol. dynamics simulations. The heterogeneous clusters melt at lower temps. as long as the relative interactions are of similar order. M.ps. do not follow a systematic trend with size, mostly due to the unusual stability of certain size clusters.