A method for feeding an antistatic compound to a polymerization reactor comprising the steps of: a) dispersing, under mixing conditions, a catalyst powder and an antistatic compound in an oil, so as to form a suspension of catalyst powder and antistatic compound in said oil; b) successively adding, under mixing conditions, a molten thickening agent to said suspension from step a), while maintaining said suspension at a temperature such that said thickening agent solidifies on contact with said suspension; c) transferring the product obtained from b) to a polymerization reactor.