In multiple clinical conditions, including trauma and hemorrhage, reperfusion magnifies ischemic tissue damage. Ischemia induces expression of multiple neoantigens, including lipid alterations that are recognized by the serum protein, β2-glycoprotein I (β2-GPI). During reperfusion, binding of β2-GPI by naturally occurring Abs results in an excessive inflammatory response that may lead to death. As β2-GPI is critical for intestinal ischemia/reperfusion (IR)-induced tissue damage and TLR2 is one of the proposed receptors for β2-GPI, we hypothesized that IR-induced intestinal damage and inflammation require TLR2. Using TLR2(-/-) mice, we demonstrate that TLR2 is required for IR-induced mucosal damage, as well as complement activation and proinflammatory cytokine production. In response to IR, TLR2(-/-) mice have increased serum β2-GPI compared with wild-type mice, but β2-GPI is not deposited on ischemic intestinal tissue. In addition, TLR2(-/-) mice also did not express other novel Ags, suggesting a sequential response. Unlike other TLRs, TLR2(-/-) mice lacked the appropriate Ab repertoire to induce intestinal IR tissue damage or inflammation. Together, these data suggest that, in addition to the inflammatory response, IR-induced injury requires TLR2 for naturally occurring Ab production.