A continuous process for the production of alkali metal salts of nitrilotriacetic acid by reaction in a first stage of alkali metal cyanide, formaldehyde and excess ammonia at superatmospheric pressure and elevated temperature to form an aminoacetic acid solution, followed by depressurizing and treating the solution obtained with further amounts of alkali metal cyanide and formaldehyde while removing the ammonia formed until conversion to nitrilotriacetic acid is complete.