(2-chloroethyl)phosphonic acid (ethephon) is a well-known stimulant commonly used to increase latex production in the rubber tree (Hevea brasiliensis). In order to improve and prolong its stimulating activity, various macromolecular derivatives were synthesised incorporating ethephon. The two types of derivatives prepared were: (i) 1,4-polyisoprene support of ethephon in which ethephon molecules were bonded to rubber chains by a weak chemical bond and (ii) biodegradable polycondensates of poly(silyenephosphonate) in which ethephon molecules were inserted into the chains. The ability of these macromolecular compounds to release ethylene was evaluated from in vitro tests carried out at laboratory level. The results were compared against ethephon as the ethylene release reference.