Presently available113mSn.113mIn generators use high specific activity113Sn which cannot be produced in low and medium flux research reactors even with enriched112Sn. This paper describes a method of preparing112Sn.113mIn generators usingll3Sn of relatively low specific activity (2—3 Ci/g) obtained by irradiation of enriched112Sn in CIRUS. In this modified procedure,113SnCl4is firmly adsorbed on hydrous zirconia from 3—4 M NaCl solutions of pH 1.3 to 1.5 and the elution of113mIn is effected by dilute HCl. The generator yields 70% of the theoretically availablell3mIn activity.113Sn breakthrough has been consistantly less than 0.01% of the113mIn activity. Stable zirconium contamination in the eluate has been estimated to be less than 1 ppm. The performance characteristics of different varieties of hydrous zirconia have been studied to evaluate the optimum tin loading, indium elution and soluble zirconium contamination. Generators containing upto 700 mCi of tin-113 have been prepared yielding pure indium-113m suitable for medical use.