The invention provides a process for preparing emulsions of organopolysiloxanes (O), which includes polymerizing: (1) 100 parts by weight of hydroxyl-terminated organopolysiloxanes and (2) at least 0.01 part by weight of trialkylsilyl-terminated organopolysiloxanes having a viscosity of at least 55 mm2/s in the presence of (3) acidic catalyst and (4) emulsifier in an aqueous medium until the desired molecular size is reached.