The present invention relates to a method for preparing di-organo-dialkoxysilanes, in particular di-organo-dialkoxysilanes wherein one or both of the organic substituents are bulky. The method comprises reacting a tetraalkoxysilane compound with a first Grignard reagent to form a mono-organo-tri-alkoxysilane compound, which is then reacted with a chlorinating agent to form a chlorinated mono-organo-di-alkoxysilane which is then reacted with a second Grignard reagent to form the di-organo-di-alkoxysilane compound.