BACKGROUND:: Second-line bismuth-containing quadruple therapy is complex and frequently induces adverse effects. A triple rescue regimen containing levofloxacin is a potential alternative; however, resistance to quinolones is rapidly increasing. AIM:: To evaluate the efficacy and tolerability of a second-line triple-regimen-containing levofloxacin in patients whose Helicobacter pylori eradication treatment failed and to assess whether the efficacy of the regimen decreases with time. METHODS:: Design: Prospective multicenter study. Patients: In whom treatment with a regimen comprising a proton-pump inhibitor, clarithromycin, and amoxicillin had failed. Intervention: Levofloxacin (500 mg bid), amoxicillin (1 g bid), and omeprazole (20 mg bid) for 10 days. Outcome: Eradication was confirmed using the C-urea breath test 4 to 8 weeks after therapy. Compliance/tolerance: Compliance was determined through questioning and recovery of empty medication envelopes. Incidence of adverse effects was evaluated by means of a questionnaire. RESULTS:: The study sample comprised 1000 consecutive patients (mean age, 49±15 y, 42% men, 33% peptic ulcer) of whom 97% took all medications correctly. Per-protocol and intention-to-treat eradication rates were 75.1% (95% confidence interval, 72%-78%) and 73.8% (95% confidence interval, 71%-77%). Efficacy (intention-to-treat) was 76% in the year 2006, 68% in 2007, 70% in 2008, 76% in 2009, 74% in 2010, and 81% in 2011. In the multivariate analysis, none of the studied variables (including diagnosis and year of treatment) were associated with success of eradication. Adverse effects were reported in 20% of patients, most commonly nausea (7.9%), metallic taste (3.9%), myalgia (3.1%), and abdominal pain (2.9%). CONCLUSIONS:: Ten-day levofloxacin-containing therapy is an encouraging second-line strategy, providing a safe and simple alternative to quadruple therapy in patients whose previous standard triple therapy has failed. The efficacy of this regimen remains stable with time.