Anabolic activity of 1,5-bis(1-carbethoxy-2-oxocyclopentyl-1) pentane in a dose of 1 mg per 100 g of body weight manifests itself in an accelerated growth of the animals, increased weight of m. levator ani and also in a rise of the protein level in the blood and the skeletal muscle. Because of the absence of androgenic properties in the substance under consideration its anabolic coefficient is twice as high by comparison with methylandrostendiol. Following hypophysectomy there could be observed a certain decline in the anabolic activity of 1,5-bis(1-carbethoxy-2-oxocyclopentyl-1)pentane.