It sounds like it's doing everything through a single, logged operation. As long as you do this, you'll need this much space, as Lynn says. You either have to live with it, or change something. You could break the procedure up to a bunch of small procedures, each that commits the data move when it's done, so that the transactions are smaller and more discrete. Another option would be to use a minimally-logged operation such as bcp or BULK INSERT.