We studied the C-reactive protein level and its predictive value for early and late arrhythmia recurrences after atrial fibrillation (AF) ablation. We analysed data from 125 consecutive patients (52% with paroxysmal AF) who underwent a first AF ablation. C-reactive protein level was determined at baseline and at Days 1, 2, and 3 post-AF ablation. An early recurrence (ER) was defined as any arrhythmia occurring within the first month following the index ablation. Sixty-eight patients (54%) experienced ER. Twenty-nine patients were re-ablated for ER within the first month and were not included for the long-term follow-up analysis. Of the remaining 96 patients, 59 (61%) experienced late recurrences. C-reactive protein level increased significantly after AF ablation with a peak (40 +/- 32 mg/L) occurring 2 days after the index procedure. Patients without ER had a significant higher C-reactive protein level (49 +/- 52 vs. 32 +/- 22 mg/L, P=0.02) compared with patients without ER. However, the C-reactive protein level was similar in patients with or without late recurrences. C-reactive protein level was the only independent predictor of ERs (P = 0.03). C-reactive protein level increased significantly after AF ablation. High C-reactive protein level was associated with fewer early arrhythmia recurrences. No relationship was found between C-reactive protein level and late arrhythmia recurrences.