Despite of several attempts to demonstrate the poarathyroid gormone like substance in bovine blood, there was no good method for the extraction. A new method for the extraction from bocine plasma was established by the authors, and this method was an improved method of AURBACH's phenol method which was the most suitable method hiter-to. The substance which was obtained by the method had the following profitable characters: 1) The parathyroid hormone like substance was obtained a range from 0.08 to 0.3 in 100ml of bovine blood by this method. 2) The purified white powder of this substance was slightly soluble in water and the pH of solution showed a range from 4.8 to 5.2. ....