A series of Cs-borosilicate glasses containing 10 wt% Cs₂0 havebeen prepared and characterised. CaO, Ti0₂, ZnO and MnO, alone and in combination, have been incorporated in the glass to modify the physico-chenlical properties including formation temperature, chemical durability and Cs volatilisation. Based on the detailed studies, three glass formulations have been shortlisted. Leaching tests for periods up to 21 days and measurement of the extent of Cs volatilisation have been carried out with these three shortlisted formulations. The results of the study are useful for the selection of glass formulations for possible use as radiation sources in medical irradiators.