Abstract: This invention relates to the polymerization of organopolysiloxanes to form organopolysiloxanes of increased molecular weight and to the organopolysiloxane compositions thus produced. The organopolysiloxane is in admixture with a molten wax during the polymerization, thereby forming a blend of the wax with an organopolysiloxane of increased molecular weight. After the polymerisation reaction is completed, the reaction product can be cooled below the solidification temperature of the wax, for example down to room temperature. This yield a paste-like solid blend which is a very intimate dispersion of wax in organopolysiloxane or vice versa. The dispersion is surprisingly stable.