Porous biocompatible composite biomaterial, useable as a drug delivery system or as spacer or as bone substitute, such as for example for filling bone lacunae or for substituting damaged parts of bone tissue, or for fixing prosthesis of various types, or for thickening bones weakened by illness such as osteoporosis or the like, including a component adapted to form a porous structural matrix and a soluble component, wherein the soluble component is in form of powder and granules or other similar agglomerates so as to have mechanical support characteristics and osteoinductive and osteoconductive characteristics in the entire volume occupied by the biomaterial, and a method for obtaining the biomaterial.