Abstract: Short chain linear amidosiloxanes of the formula ##STR1## where R is a methyl, ethyl, or phenyl radical, R' is a methyl, ethyl, or 2-(perfluoroalkyl)ethyl radical, R" is a methyl or vinyl radical, and R''' is a methyl or ethyl radical and x is an integer of from 3 to 20 and mixtures of these amidosiloxanes are useful as treating agents for reinforcing silica fillers.