Hypothesis: Although laparoscopic posterior adrenalectomy (LPA) offers a more direct access to the adrenal gland, it is not as popular as laparoscopic transabdominal adrenalectomy, and the worldwide experience has been limited. We hypothesized that LPA is a safe and efficacious procedure that could best serve certain patients with adrenal tumors. Design: Case series of patients undergoing laparoscopic adrenalectomy in a single institution. Setting: University teaching hospital. Patients: Medical records of 31 patients with 33 tumors who underwent LPA were reviewed. Indications for operation included hormone secretion in 23 patients (74%), suspected or known malignant neoplasms in 7 patients (23%), and local symptoms in 1 patient (3%). Intervention: The LPAs were performed with the patients in prone position. Preoperative ultrasonography localized the adrenal tumor and kidney to guide balloon trocar placement for the creation of a working retroperitoneal space. The LPAs were performed with three 10-mm trocars using laparoscopic ultrasound to localize the tumor and the harmonic scalpel to perform the dissection. Main Outcome Measures: Demographic data, type and size of tumor, operative time, blood loss, intraoperative and postoperative complications, and hospital stay were analyzed. Results: All operations were successfully completed without conversion. Excluding the bilateral cases, the mean ± SD operative time was 176 ± 104 minutes. Estimated blood loss averaged 32 mL (range, 10-200 mL). There were no intraoperative complications. The mean±SD tumor size was 3.2±1.8 cm (range, 0.8-7.0 cm). Pathological evaluation revealed benign tumors in 25 patients (81%) and malignant tumors in 6 patients. The average hospital stay was 1.4 days (range, 1-3 days). There were no deaths. Conclusions: Although technically more demanding, LPA should be considered in patients with tumors less than 6 cm, bilateral tumors, or extensive previous abdominal surgery.