Membranes of latex extracted of the seringueira tree (Hevea brasiliensis), genetically improved by selection and statistics methods, were prepared by air drying a 10 mL suspension of the ammonia in latex 10% (v/v). TG-DTG and DSC curves were used to characterize the membranes. Thermal stability and thermal decomposition of these compounds were analyzed. The results obtained show no differences among latex from different clones.