The substance silicon dioxide, silanated, with FCM substance No 87, is authorised for use as an additive in all types of plastics, without restriction. The re-evaluation of the substance was requested based on the fact that the substance has always been produced on the basis of synthetic amorphous silicon dioxide in nanoform. Information on the basic (untreated) silicon dioxide, the surface treated silicon dioxide, silanated, and a study investigating the migration potential of the silanated silicon dioxide were provided. Having examined the information provided, the CEF Panel concluded that the information provided demonstrates adequately the absence of isolated primary nanoparticles in the basic silicon dioxide and in the silanated silicon dioxide since only aggregates larger than 100 nm along with larger agglomerates were observed using two independent measurement techniques, one of which was transmission electron microscopy (TEM). The particle size range was not affected when the silanated product was incorporated into a low density polyethylene film at 3 % w/w. Furthermore, there was no detectable migration of silicon dioxide, of any particle size, from this film into appropriate food simulants. Therefore at the particle sizes reported, the substance silicon dioxide, silanated, does not raise a safety concern for the consumer in the currently authorised conditions of use.