Synthetic hydroxyapatites containing metal oxides were precipitated from solution and characterized using both structural and chemical techniques. The electrical conductivity of M-10(PO4)(6)(OH)(2) (M = Ca, Pb, Ba) hydroxyapatites has also been measured, In these compounds, protons are the main charge carriers, The most pronounced effect of substitution on conduction properties was observed with lead containing hydroxyapatites. The resulting frequency-dependent conductivity displays a behavior characteristic of structurally distorted solid electrolytes. The relation between structure and electrical properties is discussed.