Background: Functional adrenal gland tumor is a tumor that presents with abnormal producing excess aldosterone hormone and affects the functionality of renin angiotensin aldosterone system which can be treated by laparoscopic adrenalectomy. The adrenal surgery can be approached in many techniques, such as transperitoneal and retroperitoneal approach. Materials and methods: The inclusion criterion was all patients who had diagnosed with functional adrenal gland tumor underwent laparoscopic adrenalectomy since 2011–2017 at the Srinagarind Hospital, the Faculty of Medicine, Khon Kaen University, Thailand. Patients with a lesion more than 8 cm and patients with suspected metastatic lesions were excluded. Baseline clinical features, results of clinical evaluation, pathology, operative reports, and outcome of treatment were recorded. Results: Seventy patients were treated with transperitoneal laparoscopic adrenalectomy. There were 18 men and 52 women. Mean age was 46.30 ± 11.88 years. All patients were presented with hypertension and 7 cases were presented with hypokalemia. Major histologic finding was adenoma. The mean operating time was 99.29 ± 45.66 minutes, estimated blood loss 82.36 ± 202.14 mL, and mean postoperative length of stay was 3.80 ± 2.34 days. Complications were occurred in six patients. Conclusion: Transperitoneal laparoscopic surgery had good outcomes for functional adrenal gland tumor.