Stepwise circumferential and focal radiofrequency ablation using the HALO system is a novel and promising ablative modality for Barrett's esophagus. Primary circumferential ablation is performed using a balloon-based bipolar electrode, while secondary treatment of residual Barrett's epithelium is performed using an endoscope-mounted bipolar electrode on an articulated platform. It has been used as a single-modality treatment or in combination with other therapies. Recent studies suggest that this ablation technique is highly effective in removing Barrett's mucosa and its associated dysplasia without the known drawbacks of photodynamic therapy or argon plasma coagulation, such as esophageal stenosis and subsquamous foci of intestinal metaplasia (also known as "buried Barrett"). [nl]In this review paper we will explain the technical background of radiofrequency ablation using the HALO system, give a summary of its current status, and speculate on possible future applications.