Few clinical studies have demonstrated an anti-proliferative activity of somatostatin (SST) analogs in carcinoids. We report the case of a woman with liver metastases of neuroendocrine tumor and no evidence of the primary tumor. The liver metastases were characterized by high proliferation index, immunoreactiviy for somatostatin receptor (SSTR)-l, 2, 3 and 5 and positive octreoscan. Urinary 5-hydroxyindolacetic acid, serum serotonin and chromogranin A were elevated. Slow release lanreotide (SR-LAN) therapy for 3 mo controlled clinical and biochemical signs of carcinoid tumor and caused a clear-cut reduction in the diameter of two liver metastases and disappearance of another lesion, with further reduction after 6 and 18 mo. We demonstrated a clear-cut long-lasting anti-proliferative effect of SR-LAN on liver metastases of occult carcinoid with high proliferation index and immunoreactivity for SSTR-1, 2, 3, and 5. Immunohistochemistry for SSTRs could be a suitable method for the selection of patients with metastatic carcinoid that may benefit from SST analog therapy. Few clinical studies have demonstrated an anti-proliferative activity of somatostatin (SST) analogs in carcinoids. We report the case of a woman with liver metastases of neuroendocrine tumor and no evidence of the primary tumor. The liver metastases were characterized by high proliferation index, Slow release lanreotide (SR-LAN) therapy for 3 mo controlled clinical and biochemical signs (SSTR) -l, 2, 3 and 5 and positive octreoscan. of carcinoid tumor and caused a clear-cut reduction in the diameter of two liver metastases and disappearance of another lesion, with further reduction after 6 and 18 months. We demonstrated a clear-cut long-lasting anti-proliferative effect of SR-LAN on liver metastases of occult carcinoid with high proliferation index and immunoreactivity for SSTR-1, 2, 3, and 5. Immunohistochemistry for SSTRs could be a suitable method for the selecti on of patients with metastatic carcinoid that may benefit from SST analog therapy.