The dehydrogenation and aromatization of propane over Re/HZSM-5 and Ga/HZSM-5 was investigated at temperatures ranging from 623 to 923 K under atmosphere pressure. The strong acid sites declined upon introduction of rhenium to HZSM-5, and were not influenced by gallium. Compared with Ga/HZSM-5, Re/HZSM-5 exhibited remarkable enhancement of propane dehydrogenation while the decomposition slowed down with time on stream. Addition Of CO2 (30%) to the feed obviously inhibited the transformation of propane and the selectivity to aromatics. In contrast, addition of methane enhanced the selectivity to aromatic products. Meanwhile, formation of methane from propane was inhibited and the methane from the starting mixture was transformed. (c) 2005 Elsevier B.V. All rights reserved.