AbstractIn the course of an investigation dealing with the utilization of D‐mannitol and inorganic phosphate byAbsidia glaucait was found necessary to confirm the existence and establish the identity of the 1‐Phosphate ester of this polyol. This paper describes the synthesis of radioactive mannitol‐1‐phosphate labeled with carbon‐14 and phosphorus‐32 by a modification of the procedure of Seegmiller and Horecker (1951) for the synthesis of glucose‐6‐phosphate. In addition we document the paper and gel chromatographic behavior on Sephadex G‐15 of the products and32PPA prepared by the method of Bell (1948) for the synthesis of po