A series of 100 prolactin secreting pituitary adenomas was reviewed and demonstrated an early cure rate of 85.2% with a cure rate of 89% if prolactin was less than 200 ng/ml. For macroadenomas the cure rate was 50% giving an overall cure rate of 71% for the entire group. When long term (greater than 5 years) followup was obtained a 17% incidence of recurrence was noted for the microadenoma group with a 20% recurrence rate for the macroadenoma group. Secretory dynamic studies were done shortly after surgery and then after a delay. Many showed a return to normal prolactin secretory dynamic suggesting that the underlying hypothalamic regulation is normal in most patients. Abnormal secretory dynamics at 6 weeks post operative testing were not predictive of which patients would relapse as many patients who had abnormal dynamics early did not relapse even during prolonged followup. Conversely a normal response to provocative testing did not preclude late relapse. A similar series of 40 consecutive patients with Cushing's disease was reviewed. Tumor was found in all but three cases. 84% of patients were cured and thus far only one patient (2.5%) has shown late recurrence with this occurring at 6 2/3 years following surgery with normal stimulatory dynamics present for five years. The implication is that hypothalamic regulation is normal in Cushing's disease as well. The differences in recurrence rates may be reflective of the aggressiveness with which one disease is treated, with the acceptance of a higher incidence of hypopituitarism as a consequence of more radical surgery for Cushing's disease.