OBJECTIVES: There is a lack of evidence regarding preference-based utility weights for key efficacy and safety outcomes associated with immuno-oncology treatments for patients with resected high-risk melanoma. METHODS: A cross-sectional study in the general adult population was conducted in the United Kingdom (UK) and Australia to obtain utilities for current health and 14 adjuvant melanoma health states (adjuvant treatment no toxicities, induction treatment, no treatment, fatigue, nausea, rash, influenza, diarrhea, toxicity- outpatient, depression, hypophysitis, long term survival, toxicity- hospital and recurrence of cancer). The descriptions of the health status were developed in layperson terms, and were refined with input from two clinical experts and a pilot test with 10 individuals from the general public (5 UK; 5 Australia). One-on-one interviews were conducted using the standard gamble technique. Utility weights range from 0.0 (dead) to 1.0 (full health). Supplemental open-ended questions addressed the maximum acceptable risk they were willing to accept for a treatment with different levels of effectiveness. RESULTS: Among 155 participants (52% male; mean age, 46 years) ‘adjuvant treatment no toxicities’ (0.89) was most preferred, followed by ‘induction treatment’ (0.88), and ‘no treatment’ (0.86). Participants least preferred ‘cancer recurrence’ (0.62); the utility for ‘cancer recurrence and 10-year survival with treatment’ was 0.70. Dis-utilities for grade 2 toxicities ranged from -0.06 for fatigue to -0.13 for hypophysitis. The mean maximum acceptable risk of suffering a life-threatening event ranged from 30% for an increase of 6% in the chance of remaining cancer free over 3 years, to a maximum acceptable risk of 40% for an 18% increase in remaining cancer free; Australian respondents had higher maximum acceptable risk estimates than UK respondents. CONCLUSIONS: Preference weights for adjuvant melanoma health states were obtained from the general population in two countries. These utilities can be incorporated into treatment specific cost-effectiveness evaluations.