Retreatment with ipilimumab has been shown to re-establish disease control in some patients with disease progression. Here, we report the efficacy and safety of retreatment with ipilimumab 3 mg kg(-1) among patients participating in an expanded access programme in Italy.Patients who achieved disease control during induction therapy were retreated with ipilimumab upon progression (3 mg kg(-1) every 3 weeks for up to four doses), providing they had not experienced toxicity that precluded further dosing. Tumour assessments were conducted after retreatment, and patients were monitored throughout for adverse events.Of 855 patients treated with ipilimumab, 51 were retreated upon disease progression. Of these, 28 (55\%) regained disease control upon retreatment and 42\% were alive 2 years after the first induction dose of ipilimumab; median overall survival was 21 months. Eleven patients (22\%) had a treatment-related adverse event of any grade during retreatment. These were generally mild-to-moderate and resolved within a median of 4 days. No new types of toxicity were reported.For patients who meet predefined criteria, retreatment with ipilimumab is generally well tolerated and can translate into clinical benefit. This strategy should be compared with other therapeutic options in randomised controlled trials.