Background: Certolizumab pegol (CERT) is indicated for reducing the signs and symptoms of Crohn's disease (CD) and maintaining clinical response. Patients losing response received an extra "capture" re-induction dose in the PRECiSE 4 study. We examined the use of certolizumab in a retrospective cohort of patients with CD at a single inflammatory bowel disease center. Methods: We conducted a retrospective chart review of all adult patients with CD treated with CERT at the University of Chicago from April 22, 2008 to May 1, 2011. Demographics, disease characteristics, inflammatory bowel disease therapies, surgeries, CERT dosing, and clinical outcomes were recorded. Predictors of clinical response, re-induction dosing, and maintenance dose escalation were evaluated. Univariate, multivariate, and Kaplan-Meier analyses were performed for predictive variables of clinical response, re-induction dosing, and maintenance dose increases. Results: One hundred ten patients were identified; 23 were excluded. The remaining 87 patients had a sustained clinical response of 31.0%, remission of 14.9%, minimal or no response of 31.0%; 37.9% initially responded but lost response. In total, 35.6% of patients received a single re-induction dose of 400 mg after a mean of 29 weeks, predicted by prior anti-tumor necrosis factor (P = 0.007) and absence of perianal disease (P = 0.006); only 5 patients (16.1%) maintained a durable response or remission; 11.5% increased maintenance dosage after a mean of 50 weeks; all but 1 subsequently stopped CERT. Conclusions: Some patients with CD (31%) achieved a sustained response. The majority of patients receiving re-induction dosing did not achieve a sustained clinical response. Previous treatment with anti-tumor necrosis factor therapy was associated with reduced responses, suggesting that CERT may be more effective as an initial anti-tumor necrosis factor therapy.