The 29Si and 13C NMR chemical shifts are reported for trimethylsilyl derivatives of 25 aminoacids, the majority of which occur naturally as protein constituents of foodstuffs. The 29Si chemical shifts in trimethylsilyl esters of aminoacids roughly correlate linearly with the pK values of the parent aminoacid. No such simple correlations were found for the shifts in the fully trimethylsilylated amino