Abstract Fluororganic and/or sterically hindered cyanohydrines are useful synthetic reagents, not readily available directly from e.g. aldehydes or ketones and hydrogen cyanide. By using trimethylsilyl cyanide (TMSCN), the obtained O-Silyl-cyanohydrines can be applied successfully for the same purpose. Selected examples of the type R1R2C-CN(OSiMe3) 1 -12 are presented which prove the extensive applicability of this reaction [R = (fluoro)alkyl, (fluoro)aryl, anthryl, cyclopropyl, CCl3, CBr3 etc.]. Malodinitrile derivatives RC(CN)2OSiMe3 14 were obtained from carboxylic acid chlorides, α-, β- and 7 -Diketones react with formation of the corresponding linear or cyclic doubly substituted O-Silylcyanohydrines 16, 17, 21, 22. The enol-form of hexafluoroacetylacetone reacts with silylation to give the E-isomer of the silylenol ether 18, the carbonyl group of which forms the O-Silylcyanohydrine 19. With Me2Si(CN)2 both reaction steps occur intramolecular, yielding a 2,6-dioxa-l-sila-3-cyclohexene 20.