A procedure for the determination of both 32P and phosphate contents on the same sample has been described. Following phosphate estimation by the method of Bartlett (5), the solution containing the blue reduced phosphomolybdate complex is decolorized at high pH. 32P is measured in this transparent aqueous solution with a liquid scintillation spectrometer, without the addition of scintillators, by utilizing the Čerenkov radiation. © 1969.