Summary Background The European Organisation for Research and Treatment of Cancer (EORTC) 1325-MG/KEYNOTE-054 trial in patients with resected, high-risk stage III melanoma demonstrated improved recurrence-free survival with adjuvant pembrolizumab compared with placebo (hazard ratio 0·57 [98·4% CI 0·43–0·74]; p<0·0001). This study reports the results from the health-related quality-of-life (HRQOL) exploratory endpoint.