A method has been devised for the quantitative estimation of microgram and nanogram quantities of histamine as its Natrifluoroacetyl-N -carbethoxy derivative. Trifluoroacetic anhydride was used for the formation of Na-trifluoroacetyl derivative and ethoxyformic anhydride was used for the N carbethoxy derivative. Quantitative determinations were made in the range of 20 to 100 micrograms and 250 and 1000 nanograms with a mean standard deviation of 2-3%. The standard curves were linear. im im-40 5