It is found experimentally that; mandelic acid is an excellent masking agent for titanium (Ⅳ) at pH 3.0 to 7.0.It.can quantitatively displace EDTA from the Ti-EDTA complex without, the interference from zirconium, thorium, iron, bismuth, aluminum, gallium, indium, cerium and other rare earths, copper, lead, zinc, nickel, cobalt, cadmium, manganese etc.It is also found that mandelic; acid is much supc;rior to lactic acid, which was found to be a good masking agent for titanium.When the EDTA displaced from the Ti-EDTA complex with lactic acid vvastitrated with a standard nitrate solution,the end point only lasted for 10 to 20 seconds if aluminium was present, because lactic acid could slowly displace EDTA from the Al-EDTA complex.We found that mandelio acid does not mask aluminum.This makes possible the stepwise titrations of iron, titanium and aluminum using mandelic acid and ammonium fluoride as masking agents.