The preparation of insoluble stannic molybdate precipitate was radiometrically investigated using Na2MoO4-99Mo solution. For routine preparation of the precipitate, equal volumes of stannic chloride and sodium molybdate solutions (1.08: 1 M/M) were stirred together at 27°C. Stannic molybdate-99Mo precipitates prepared from Na2MoO4-99Mo solutions are a good source for99mTc-generator. Greater than 60% of the precipitate available99mTc activity could be eluted in 25 ml of isotonic saline solution. Radionuclidic, radiochemical and chemical analysis of the99mTc eluted proved to be proper for medical use. On the otherhand, thermal neutron irradiation of inactive stannic molybdate precipitates are not a suitable source for pure99mTc column-eluates.