A method of determining phosphate P in fresh plant tissue is outlined. The tissue is extracted with dilute H2SO4 and cleared with phosphate-free powdered charcoal or carbon black. The method of Fiske and Subbarow is used on the cleared extract. Data are presented which show good duplicates on tomato, tobacco and lettuce leaves. No adsorption of phosphate by the charcoal used could be detected. Preference is given to 1, 2, 4-amino-naphtholsulphonic acid over stannous chloride as a reducing agent, because: The reagent keeps better, it does not require as narrow a range of acidity for accuracy, a blue color does not develop in the absence of phosphate at any degree of acidity used in these experiments, and larger quantities of Fe may be present in the tissue extract without causing interference.