Process for the preparation of a calcium phosphate bone foam wherein the foam is obtained by the mixture of at least two phases, a) a first phase comprising water, a propellant in an amount of between 5% and 25 % by weight/weight based on the first phase, and a stabilizing agent in an amount of between 0,1 % and 10 % by weight based on the first phase, b) a second phase comprising one or more sources for calcium and/or phosphate selected from the group consisting of a') at least a source of calcium and/or phosphate selected from tetracalcium phosphate, dicalcium phosphate anhydride, dicalcium phosphate dihydrate, alpha tricalcium phosphate, beta tricalcium phosphate, monocalcium phosphate monohydrate, hydroxyapatite, calcium deficient hydroxyapatite, fluorapatite, amorphous calcium phosphate, calcium- sodium- and potassium-phosphate, calcium- and sodium- phosphate, calcium- and potassium-phosphate, and calcium pyrophosphate; or alternatively, b') at least a compound of calcium selected from calcium carbonate, calcium sulphate, calcium sulphate hemi hydrate, calcium oxide, and calcium hydroxide, and at least a compound of phosphate selected from phosphoric acid and all the soluble phosphates; or alternatively c') a mixture of at least a compound defined in option a) and at least a compound defined in option b), and wherein the foaming is performed during the mixture of the at least two phases and wherein the calcium phosphate foam has a viscosity of between 100 and 100.000 cP at 20 °C. a) a first phase comprising water, a propellant in an amount of between 5% and 25 % by weight/weight based on the first phase, and a stabilizing agent in an amount of between 0,1 % and 10 % by weight based on the first phase, b) a second phase comprising one or more sources for calcium and/or phosphate selected from the group consisting of a') at least a source of calcium and/or phosphate selected from tetracalcium phosphate, dicalcium phosphate anhydride, dicalcium phosphate dihydrate, alpha tricalcium phosphate, beta tricalcium phosphate, monocalcium phosphate monohydrate, hydroxyapatite, calcium deficient hydroxyapatite, fluorapatite, amorphous calcium phosphate, calcium- sodium- and potassium-phosphate, calcium- and sodium- phosphate, calcium- and potassium-phosphate, and calcium pyrophosphate; or alternatively, b') at least a compound of calcium selected from calcium carbonate, calcium sulphate, calcium sulphate hemi hydrate, calcium oxide, and calcium hydroxide, and at least a compound of phosphate selected from phosphoric acid and all the soluble phosphates; or alternatively c') a mixture of at least a compound defined in option a) and at least a compound defined in option b), and wherein the foaming is performed during the mixture of the at least two phases and wherein the calcium phosphate foam has a viscosity of between 100 and 100.000 cP at 20 °C. a') at least a source of calcium and/or phosphate selected from tetracalcium phosphate, dicalcium phosphate anhydride, dicalcium phosphate dihydrate, alpha tricalcium phosphate, beta tricalcium phosphate, monocalcium phosphate monohydrate, hydroxyapatite, calcium deficient hydroxyapatite, fluorapatite, amorphous calcium phosphate, calcium- sodium- and potassium-phosphate, calcium- and sodium- phosphate, calcium- and potassium-phosphate, and calcium pyrophosphate; or alternatively, b') at least a compound of calcium selected from calcium carbonate, calcium sulphate, calcium sulphate hemi hydrate, calcium oxide, and calcium hydroxide, and at least a compound of phosphate selected from phosphoric acid and all the soluble phosphates; or alternatively c') a mixture of at least a compound defined in option a) and at least a compound defined in option b), and