Abstract: The invention concerns a method for the electrochemical deposition of hydroxyapatite layers onto metal and ceramic surfaces, the actual electrochemical coating being combined with a pre-coating of the substrates by sol-gel processes, using a calcium and (hydrogen) phosphate-containing electrolyte by means of pulsed direct current. Materials coated in this way are used in the form of biocompatible implants in human and veterinary medicine and are distinguished by particularly high grow-in rates. In contrast to conventional methods of generating hydroxyapatite layers (conventional or microwave sintering of hydroxyapatite produced by the wet-chemical method, deposition by other electrochemical, plasma or laser-aided methods or by sol-gel techniques), this method is distinguished by the application of uniform hydroxyapatite coatings which adhere well and have a small amorphous portion and an optimum layer thickness (5-25 .mu.