The relative extraction efficiency of N,N,N’,N’ tetraoctyldiglycolamide (TODGA) towards Y3⁺ and Sr²⁺  was investigated from HNO3 as well as HCl medium. The separation factor (S.F.) values were found to be much higher in HCl medium as compared to those obtained from HNO₃ medium. Based on the high separation factor values obtained in the HCl media, a separation method for ⁹⁰Y from ⁹⁰Sr (containing ⁹⁰Y in secular equilibrium) has been developed in the presen twork. The purity of the separated ⁹⁰Y was ascertained from its decay profile and half-life measurements. The extracted species was determined tobe Y(X)₃   3TODGA where X  is the nitrate or the chloride anion. The thermodynamic parameters were also determined and the two phase extraction constants(log K_ex) were calculated. The extraction of Y(III) was highly exothermic and entropy destabilized and was equally favourable from both HNO₃medium as well as HCl medium.