This invention relates to sequential methods of cryopreserving bone marrow stromal cells that are transfected and used for gene therapy by transplantation. These methods include the following steps in various orders: obtaining the cells, expanding the cells in culture, transfecting the cells, and cryopreserving the cells. With these methods, populations of bone marrow stromal cells can be acquired that are large enough to be useful in a number of therapies. Further, these large populations can be stored for extended periods of time for immediate use when needed.