Basic and clinical studies have suggested that inflammation predisposes to atrial fibrillation (AF). We assessed the association of 12 circulating inflammatory biomarkers (i.e., C-reactive protein, fibrinogen, interleukin-6, intercellular adhesion molecule-1, lipoprotein-associated phospholipase A2 [mass and activity], monocyte chemoattractant protein-1, myeloperoxidase, CD40 ligand, osteoprotegerin, P-selectin, and tumor necrosis factor receptor II) with incident AF in 2863 Framingham Offspring Study participants (mean age 60.7 years, SD = 9.4, 55% women). During follow-up (median 6 years), 148 participants (43% women) developed incident AF. In the multivariable proportional hazards models, the inflammatory biomarker panel was associated with incident AF (p = 0.03). With stepwise selection (p <0.01 for entry and retention), log-transformed osteoprotegerin was associated with incident AF (hazard ratio per SD 1.30, 95% confidence interval 1.08 to 1.56, p = 0.006). Adjusting for interim myocardial infarction or heart failure attenuated the association between osteoprotegerin and incident AF (hazard ratio 1.18, 95% confidence interval 0.98 to 1.43, p = 0.09). In conclusion, circulating osteoprotegerin concentration was significantly associated with incident AF in our community-based sample, possibly mediated by interim cardiovascular events.