The acid dissolution of precipitated hydroxyapatites with carbonate (0.5-9.2 wt%), with and without zinc being added (0.02-2.2 wt%) was studied. Calcium and phosphate loss varied close to linear for the first 50 min of dissolution. Markedly lower dissolution values were obtained for the Zn-containing samples than for the non-zinc ones. The incorporation of zinc into the crystal lattice of carbonated hydroxyapatite reduces the acid reactivity, most likely due to the formation of crystals with less structural defects.