Recently, extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has been more frequently isolated from blood specimens than in the past. In this study we investigated a panel of therapeutic agents used to treat 37 patients with ESBL-producing E. coli bacteremia. Antimicrobial agents administered as definitive therapy displayed higher efficacy rates than when empiric therapy was administered (efficacy rates, 95.7% vs. 62.5%). The success rate of carbapenem was 95.8% (23/24) in patients with ESBL-producing E. coli bacteremia. In addition, the success rate of cefmetazole against ESBL-producing E. coli sensitive to this drug was 87.5% (7/8). In conclusion, patients at high risk of infection due to ESBL-producing E. coli should be empirically treated with carbapenem antibiotics. In addition, cefmetazole may be a treatment option for patients with ESBL-producing E. coli bacteremia.