A process for the preparation of polyolefins carried out in the presence of an antistatic composition made from or containing:a) a compound of formula R—OH wherein R represents hydrogen or a linear or branched, saturated alkyl group having from 1 to 15 carbon atoms; andb) an oligomeric or polymeric organic compound having one or more terminal hydroxyl groups and a viscosity at 40° C. of at least about 20 mm2/sec (DIN 51562).