In this review, standards of diagnosis and treatment of colorectal liver metastases are described on the basis of a workshop discussion. Algorithms of care for patients with synchronous / metachronous colorectal liver metastases or locoregional recurrent tumour are presented. Surgical resection is the procedure of choice in the curative treatment of liver metastases. The decision about the resection of liver metastases should consider the following parameters: 1. General operability of the patient (comorbidity); 2. Achievability of an R 0 situation: i. if necessary, in combination with ablative methods, ii. if necessary, neoadjuvant chemotherapy, iii. the ability to eradicate extrahepatic tumour manifestations; 3. Sufficient volume of the liver remaining after resection ("future liver remnant = FLR): i. if necessary, in combination with portal vein embolisation or two-stage hepatectomy; 4. The feasibility to preserve two contiguous hepatic segments with adequate vascular inflow and outflow as well as biliary drainage; 5. Tumour biological aspects ("prognostic variables"); 6. Experience of the surgeon and centre! Extrahepatic disease does not contraindicate hepatectomy for colorectal liver metastases provided a complete resection of both intra- and extrahepatic disease is feasible. Even in bilobar colorectal metastases and 5 or more tumours in the liver, a complete tumour resection has been described. The type of resection (hepatic wedge resection or anatomic resection) does not influence the recurrence rate. Preoperative volumetry is indicated when major hepatic resection is planned. The FLR should be 25 % in patients with normal liver, 40 % in patients who have received intensive chemotherapy or in cases of fatty liver, liver fibrosis or diabetes, and 50-60 % in patients with cirrhosis. In patients with initially unresectable colorectal liver metastases, preoperative chemotherapy enables complete resection in 15-30 % of the cases, whereas the value of neoadjuvant chemotherapy in patients with resectable liver metastases has not been sufficiently supported. In situ ablative procedures (radiofrequency ablation = RFA and laser-induced interstitial thermotherapy = LITT) are local therapy options in selected patients who are not candidates for resection (central recurrent liver metastases, bilobar multiple metastases and high-risk resection or restricted patient operability). Patients with tumours larger than 3 cm have a high local recurrence rate after percutaneous RFA and are not optimal candidates for this procedure. The physician's experience influences the results significantly, both after hepatectomy and after in situ ablation. Therefore, patients with colorectal liver metastases should be treated in centres with experience in liver surgery.