Successful long-term management of patients with Cushing's disease (CD) remains a challenge. To date, studies on the long-term outcome of patients with CD have been conducted mainly in Caucasians. Our objective was to assess the recurrence rate in patients who underwent transsphenoidal surgery (TSS) in the management of CD and to identify predictive markers for the long-term outcomes of CD in Korea. The long-term outcome in 54 patients who underwent TSS for the treatment of CD from 1984 to 2010 was retrospectively reviewed. Recurrence was defined as an elevated serum cortisol or an elevated 24 hour urine free cortisol or a suppressed serum cortisol by dexamethasone higher than 138 nmol/L. Mean age at diagnosis was 35.8 ± 12.8 years and median follow-up duration was 50.7 months. Initial successful TSS was obtained in 38 patients (70.4%). Among these 38 patients, 18 (47.4%) patients had a recurrence of CD. Preoperative serum cortisol level was significantly associated with recurrence. Pathologic confirmation of an adenoma was marginally associated with lower risk of recurrence. Positive results of imaging study and presence of microadenoma were not associated with risk of recurrence. Recurrence rate of CD after initial successful TSS was 32.4% at 5 years and 54.6% at 10 years, respectively. Following initial successful TSS, close long-term endocrine surveillance is mandatory as the recurrence rate increases with time. Preoperative serum cortisol level and pathologic confirmation of an adenoma may have a predictive value for recurrence of CD after TSS.