Human chorionic gonadotropin hormone(H.C.G.) is secreted from the villus tissues of the placenta and excreted in lange amount into the urine. Its isolation is chiefly made from the urine of a pregnant woman. Recently, Matsushima attempted isolation of H.C.G. directly from the placenta itself. In order to prepare H.C.G. from human placenta, general method of extractiag and purifying proteins was applied. Its way was as follow: Crude H.C.G. was extracted from placenta with pH 9.0 and pH 5.0 aqua ammonia, and purified with pH 8.0 ammonia and 50% ethanol at pH 4.8. The purified H.C.G. showed two moving bands on the anode by paper electrophoresis. On the other hand, the H.C.G. from pregnancy urine (Standard. Pharm. Co.) showed same two bands but their moving ratio were different. The purified H.C.G. showed gonadotropin effect when it was injected young fomale rats 40r/cc per day for 5 days and weighted the increased ovary weight.