Calcium hydroxyapatites of different compositions and various specific surface areas (SSA) are shown to be efficient catalysts for the Michael reaction involving ethyl 2-oxocyclopentanecarboxylate, methyl 2-oxocyclopentanecarboxylate, ethyl 2-oxocyclohexanecarboxylate, methyl 1-oxoindane-2-carboxylate and ethyl 3-oxo-3-phenylpropanoate with 3-buten-2-one. The reaction without solvent is nearly quantitative and leads to the expected addition products. The catalyst can be easily recovered by filtration. From deuterium labeling experiments, a mechanism based on the basic properties of the calcium hydroxyapatite surfaces is proposed to explain their ability to catalyze the Michael reaction.