PURPOSE: Surveillance imaging of asymptomatic patients with diffuse large B-cell lymphoma (DLBCL) in first remission remains controversial. A decision-analytic Markov model was developed to evaluate the cost-effectiveness of follow-up strategies following first-line immunochemotherapy. PATIENTS AND METHODS: Three strategies were compared in 55-year-old patient cohorts: routine clinical follow-up without serial imaging, routine follow-up with biannual computed tomography (CT) scans for 2 years, or routine follow-up with biannual [(18)F]-fluorodeoxyglucose positron emission tomography-computed tomography (PET/CT) for 2 years. The baseline model favored imaging-based strategies by associating asymptomatic imaging-detected relapses with improved clinical outcomes. Lifetime costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated for each surveillance strategy. RESULTS: Surveillance strategies utilizing 2 years of routine CT or PET/CT scans were associated with minimal survival benefit when compared with clinical follow-up without routine imaging (life-years gained: CT, 0.03 years; PET/CT, 0.04 years). The benefit of imaging-based follow-up remained small after quality-of-life adjustments (CT, 0.020 QALYs; PET/CT, 0.025 QALYs). Costs associated with imaging-based surveillance strategies are considerable; ICERs for imaging strategies compared with clinical follow-up were $164,960/QALY (95% CI, $116,510 to $766,930/QALY) and $168,750/QALY (95% CI, $117,440 to 853,550/QALY) for CT and PET/CT, respectively. Model conclusions were robust and remained stable on one-way and probabilistic sensitivity analyses. CONCLUSION: Our cost-effectiveness analysis suggests surveillance imaging of asymptomatic DLBCL patients in remission offers little clinical benefit at substantial economic costs.