The purpose of this study was to determine the relationship between tissue inhibitor of metalloproteinases-1 and atrial fibrillation recurrence after catheter ablation. Tissue inhibitor of metalloproteinases-1 (TIMP-1) is involved in extracellular matrix remodeling which is considered to be a marker of regulation of matrix metalloproteinase activity. An enzyme-linked immunosorbent assay prior to a radiofrequency catheter ablation (RFA) procedure was used for measuring the serum level of TIMP-1 in 210 patients: 80 patients without history of atrial fibrillation (AF) and 130 patients with idiopathic AF (paroxysmal AF – 30, persistent AF – 32, long-standing AF – 35 and permanent AF – 33). Their relationship with intraoperative efficacy and recurrence of AF was evaluated throughout the entire observation period. The observation period was 22.2 ± 7.9 months. TIMP-1 level was higher in the groups of patients with AF than in the control group: 131.51 ± 36.40, 149.5±42.7, 151.5 ± 42.7 and 155.9 ± 44.7 ng/ml for paroxysmal, persistent, long-standing and permanent forms of AF. In the control group, TIMP-1 level was 103.6 ± 14.7 ng/ml. TIMP-1 level increased with the progression of AF. A multifactor analysis showed that TIMP-1 level, history of atrial fibrillation and left atrial volume were independent predictors of sinus rhythm recovery and recurrence of AF. An increase in TIMP-1 level in patients with AF has been shown. An increase in TIMP-1 levels was observed as AF progressed. TIMP-1 is prognostic criteria of arrhythmia recurrence after RFA.