An environmentally friendly catalytic system for trimethylsilylation of alcohols and phenols with hexamethyldisilazane can be successfully carried out for the first time over sulfonated mesoporous carbon catalyst (CMK-5-SO3H) in dichloromethane at ambient temperature and excellent conversions were obtained. Furthermore, the catalyst displays high activity and thermal stability (to 200 A degrees C) and it can be reused repeatedly for at least 25 cycles without any evidence of loss of activity, confirming the stability of covalent bonding of acidic centers.