The transsilylation of hexamethyl- and heptamethyldisilazane as well as of Si-chlorinated methyldisilazanes by (CH3)2SiCl2, CH3SiCl3 and SiCl4 has been investigated. The reactivity of the disilazanes decreases as the number of Cl-atoms in these molecules increases. A reactivity order (CH3)2SiCl2 3SiCl3> SiCl4 has been observed for the transsilylating agent. The shielding of all types of CH3 groups present in the disilazanes investigated is additively dependent on the number of Cl atoms present in the molecules.