Among the modern techniques for cancer therapy, a very promising and minimally invasive treatment is implementable by using radiofrequency or microwave energy. The process is called thermoablation and is recommended for soft tissues as liver, kidney or lung because those tissues are the best environment for the so-called dielectric heating, a physical phenomenon linked to internal molecular friction generated by the application of electromagnetic field with selected frequency values. The technique involves placement of a specially designed mini-invasive probe, guided by ultrasound echography or CT, directly into the tumor mass followed by careful application of radiofrequency or microwave energy to produce accurately located thermal coagulation of the target tissue. The ablation pattern, centered around the probe tip and typically characterized by an ellipsoidal shape, extends proportionally to the overall applied energy, i.e. to the product of the RF or microwave power by the application time interval. The operation lasts a few minutes and typically requires single-day hospitalization, guaranteeing also a minimal psychological burden to the patient. The latest trends about thermoablation clearly indicate a progressive reduction of radiofrequency applications and a correspondent increase in microwave ablations thanks to higher process speed and accuracy. Moreover, the availability of latest-generation solid-state devices allows even more accurate ablation patterns, enables the application of complex pulsed waveforms and eases the implementation of real-time ablation evaluation by precise reflected energy measurement. Indeed a promising trend to help patients having a better life.