No-carrier-added 90Y was separated from 90Sr via colloid formation of 90Y in basic media. The mixture was passed through glass wool or membrane filter. The filtrate contained 90Sr, while 90Y was retained on glass wool/membrane filter. Yttrium-90 was extracted with 0.1 M HCl. Contamination of 90Sr was <0.0001%. More than 98% labeling yield of 90Y-EDTMP was confirmed by paper chromatography.