N-Ethylamino acids have been prepared by reaction of N-acetylamino acids with trimethyloxonium tetrafluoroborate (Meerwein's reagent) giving imino ether fluoroborates, followed by reduction with sodium borohydride. The use of Meerwein's reagent for the deacylation of N-acylamino and N-acyl, N-methylamino acid derivatives has been investigated.