The present invention relates to a process for the polymerization of olefins, comprising the steps of introducing at least one olefin, at least one polymerization catalyst, at least one cocatalyst and at least one cocatalyst aid, and optionally a scavenger, into a polymerization reactor, and polymerizing the olefin, wherein the cocatalyst aid is a reaction product prepared separately prior to the introduction into the reactor by reacting at least one metal alkyl compound of group IIA or IIIA of the periodic system of elements and at least one compound (A) of the formula RmXR′n, wherein R is a branched, straight, or cyclic, substituted or unsubstituted, hydrocarbon group having 1 to 30 carbon atoms, R′ is hydrogen or any functional group with at least one active hydrogen, X is at least one heteroatom selected from the group of O, N, P or S or a combination thereof, and wherein n and m are each at least 1 and are such that the formula has no net charge.