Catheter ablation is superior to antiarrhythmic drugs in maintaining sinus rhythm for patients with atrial fibrillation (AF). Pulmonary vein (PV) isolation is the cornerstone of any AF ablation procedure. Conventionally, this is achieved by performing point by point lesions using radiofrequency (RF) energy. However, this is technically challenging, time consuming and is associated with a number of complications. Long-term durability of PV isolation is also a concern. To address these issues, 'one-shot' energy delivery systems and alternative energy sources have been developed. The cryoballoon system has emerged as the most commonly used alternative to point by point RF technology. In this paper, we compare the technology, biophysics and clinical data of cryoballoon to conventional RF ablation for AF. The safety and efficacy of cryoballoon compared to RF ablation is critically reviewed. We conclude by looking at future applications of this technology.