New drugs and other medical advances in organ transplantation are expected to increase the rate of retention of transplanted kidneys, or grafts, and therefore also raise patient survival rates. In particular, the immunosuppressive drug cyclosporine has been found to reduce the likelihood of rejection of a transplanted kidney by the immune system of the transplant recipient. A critical issue is the effect changes in the graft and patient survival rates will have on the current shortage of donated kidneys. On one hand, higher survival rates may decrease the demand for transplants, as fewer people require a second or third transplant following the failure of a previous one. On the other hand, however, demand for first-time transplants may increase as more end-stage renal disease (ESRD) patients perceive transplantation as a more successful, and therefore more desirable, procedure. We used a simulation model to estimate the net effect of these changes. The results show that, all else being held constant, the increase in the survival rate resulting from medical advances could alleviate the current kidney shortage. However, if higher survival rates lead to an increased demand for transplants, the net effect would be a substantial aggravation of the current shortage of donated kidneys. That would force regional organ procurement agencies and other concerned organizations to attempt unprecedented increases in kidney donations ranging from 50% to 300% over the current rate.