ABSTRACT A relatively less expensive and less time consuming radioanalytical technique for quantitative determination of Pu in urine at the mBq level was developed. In this new method, Pu in urine is co-precipitated with Ca2C2O4 from wet oxidized urine matrix and oxalate ions is destroyed with HClO4· Pu in +4 state is extracted into 0.01M PC-88A (2-ethyl hexyl phosphonic acid mono-2-ethylhexyl ester)dissolved in toluene from optimized 2M HCl aqueous phase. Pu is stripped into 5% oxalic acid solution and is evaporated with HNO3–HClO4 mixture to destroy oxalate ions. Finally, Pu is electro deposited in ammonium oxalate medium and counted in an alpha spectrometer. The detailed study of the work is presented in this paper. An interference study on elements that are normally present in urine and other actinides (if present) was performed and is also given.