Tissue ablation of localized cancer in a variety of organs by means of radioactive seeds, alcohol, heat or frost guided by percutaneous, endoluminal or endoscopic ultrasound has gained widespread use during the last two decades. These techniques are referred to as minimal invasive therapies but differ with respect to invasiveness and complexity of the equipment, time and personnel needed and cost related to the treatment. They range from a simple set-up with a needle and a syringe containing few cc of ethanol used for ablation of parathyroid adenomas to a highly sophisticated scenario where liquid nitrogen under high pressure and low temperature is circulated from big tanks into several dedicated needleshaped probes meticulously positioned transperineally in a prostate cancer. Each method has advantages of its own and comparison of the results can only be done to a limited degree. In general ethanol has been used for ablation of hepatocellular carcinoma and parathyroid adenoma, brachytherapy mainly for prostate cancer by means of Iodine-125 seeds, cryotherapy for liver metastases, prostate cancer and renal carcinoma and finally, thermal ablation by heat with the use of laser, radiofrequency (RF), microwave or high-intensity focused ultrasound (HIFU) has been used in a range of organs on a variety of indications but, by far mostly in the treatment of colo-rectal liver metastases. Any new treatment has to be validated. For RF ablation of colo-rectal liver metastases the published data confirm that a 5 years survival rate comparable to surgical treatment i.e. 30% to 40% can be achieved.