This paper describes a method for the estimation of ⁹⁰Sr in various PUREX and THOREX process streams. Radiostrontium present in the sample is loaded on an extraction chromatographic column containing 4,4’(5’)- bis(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6) in 1-octanol impregnated on amberlite XAD-7 after diluting it appropriately in about 3.0 M HNO₃. The column is then washed using 3 M HNO₃ to remove the impurities completely and finally ⁹⁰Sr is eluted in 5 mL of water and subjected to beta counting without time delay. Recovery of ⁹⁰Sr separation is studied in presence of varying quantity of uranium and thorium in the sample. The method is used to estimate ⁹⁰Sr in actual process samples containing ⁹⁰Sr activity in wide range of activity varying from Bq/mL to Ci/L. The results are compared with those obtained by conventional radiochemical precipitation method and found to agree within ±5 %.