For palliation of pain caused by bone metastases beta radiation isotope therapy was successful. As shown in experimental work on animals bone uptake of 90Y with its shorter half-life is high when it is administered as a citrate complex. 90Y can be eluted with high purity from a 90Sr "cow". The retention in man was found by whole-body counting to be higher than 80%. In preliminary trials on 16 patients the analgetic effect was the same as that of 89Sr. The properties of 90Y therapy are discussed.