Atrial fibrillation (AF) is the commonest form of disturbed cardiac rhythm. Hundreds of thousands of AF ablations are annually performed worldwide using different energy sources. One of the most popular methods is radiofrequency catheter ablation (RFA). This treatment is fraught with various risks being a highly complicated technical procedure. This review paper presents data on the most frequent complication of RFA, their frequency, causes, diagnosis, treatment and prevention. Much attention is given to the recognition and prevention of possible complications.