β-Trimethylsilyl allenes have been prepared in fair to good yields fromallylsilanes by successive dibromocarbene addition and rearrangement of the cyclopropylidenes. In the case of 3,6-bis(trimethylsilyl)cyclohexa-1,4-diene, insertion of dibromocarbene occurs in the silicon-carbon bond leading to α-bromobenzyltrimethylsilane.