Background: 90Y microsphere radioembolization is performed by injecting the microspheres through a hepatic artery catheter placed percutaneously via the femoral or brachial artery. This study assessed the efficacy of 90Y microsphere therapy for patients with unresectable neuroendocrine tumour liver metastases (NETLMs). Potential prognostic factors were analysed for their impact on overall survival. Methods: A prospectively collected database for patients with NETLMs treated by 90Y microspheres in two centres from 2003 to 2008 was examined retrospectively. Serial radiographic evidence was collected during follow-up to assess response. Results: Fifty-eight patients were included, 51 of whom had évaluable disease at most recent follow-up. Six patients achieved a complete response, 14 a partial response, 14 had stable disease and 17 had disease progression. Overall survival rates at 1, 2 and 3 years were 86, 58 and 47 per cent respectively; median survival was 36 (range 1 -61) months. Extent of tumour involvement, radiographic response to treatment, extrahepatic disease and tumour grade were significant prognostic factors for overall survival. Conclusion: 90Y microsphere radioembolization achieved a radiographic response in a significant proportion of patients with NETLMs.