Liver metastases (LM) are common in various types of malignant diseases, either at the diagnosis of the primary tumour or at a later time point. While the resection of colorectal LM (CRLM) is a well-established procedure, with survival rates superior to chemotherapy alone, controversial data still exist on liver resection for non-colorectal LM (NCRLM) (2, 3). These patients comprise a diverse and heterogeneous group usually excluded from surgery due to advanced tumour stage or the presence of concomitant extrahepatic disease. To date, no randomized clinical trial on the surgical treatment of NCRLM has been conducted, and only few retrospective reports are available.The scope of this research project is to develop a large registry of patients undergoing liver surgery for non-colorectal liver metastases.