A new reagent isopropyl-3-pentadecylphenyl phosphoric acid (IPPA = HR) was synthesized from cardanol [I-37, 300-39-5] and was used to investigate the extraction behaviour of lanthanum(III), europium(III) and lutetium(III) from HCl and HClO4solutions into toluene. The species extracted were found to be Ln(HR2)3(where Ln = La(III) or Eu(III) or Lu(III). The extraction behaviour of above lanthanides has also been compared with yttrium and other rare earths. It was observed that the extraction increases with increase of atomic number of rare earths. In addition the extraction efficiency of IPPA has been compared with well known acidic organophosphorous extractants like di-2-ethylhexyl phosphoric acid (DEHPA) and 2-ethylhexyl-mono-2-ethylhexyl phosphoric acid (EHEHPA).