Physicochemical properties of hydroxyapatite (HAP) synthesized by neutralization method are heavily dependent on the process variables. A Plackett-Burman two-level experimental design was therefore, chosen to screen a large number of variables and to determine their effect on HAP characteristics. The sorption of cadmium ions on HAP was studied as well. Of six selected variables (temperature, mixing speed, reactant concentration, addition rate, presence of inert atmosphere and aging time), temperature has shown the strongest influence on HAP structural and sorption properties. Smaller crystallites, lower crystallinity and higher specific surface area lead to higher sorption of cadmium ions. Room temperature and no aging are preferable conditions for the synthesis of HAP with the highest sorption efficiency. (C) 2005 Elsevier B.V. All rights reserved.