Background This open-label pilot study is aimed to evaluate the efficacy and tolerability of the antidepressant duloxetine, which is effective for diabetic neuropathic pain, in the treatment of chronic oxaliplatin-induced peripheral neuropathy (OIPN). Methods We enrolled a total of 39 patients with stage III or IV colorectal cancer with chronic OIPN. They were treated with duloxetine by increasing the dose from 30 mg/day to 60 mg/ day. Patients' pain intensity was rated at baseline and 12 weeks after duloxetine administration. The severity of neuropathic pain was evaluated using the visual analog scale (VAS) score and the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3 (NCI-CTCAE v3.0). Results Nine patients (23.1%) discontinued duloxetine before the end of treatment because of adverse events. Of the remaining 30 patients, 19 patients (63.3%) had a VAS score improvement. Among them, nine (47.4%) showed a simultaneous grade improvement, and the other 10 patients (52.6%) had a stable grade according to NCI-CTCAE v3.0. Treatment with duloxetine did not impair renal or liver function and did not interfere with chemotherapy. Conclusions Duloxetine is feasible in treating chronic OIPN with tolerable toxicity at a daily dose of 60 mg/day.