OBJECTIVES: The objective of this economic evaluation was to estimate the cost-effectiveness of HuIFN-á as adjuvant treatment for patients with resected cutaneous malignant melanoma in stage IIb-III in a Swedish setting. METHODS: The economic evaluation is based on a prospective multicentre study, in which 252 patients with totally resected cutaneous melanoma in stage II-IV (whereof 158 high-risk patients with melanoma in stage IIb-III) were randomised to induction treatment with dacarbazine (DTIC) followed by six months adjuvant treatment with low-dose natural human interferon alpha (HuIFN-á) versus no adjuvant treatment. A Markov model was developed to assess the costs and clinical outcomes of DTIC/HuIFN-á compared with no adjuvant treatment. Time-to-progression and overall survival were based on data from the clinical study. The model compares two groups of patients, 54 years old at base-line, and adopts a life-long horizon. The primary clinical outcome measure is quality-adjusted life years (QALYs) gained. Direct medical costs were included in the analysis. An additional analysis was performed that included costs of added years of life for the Swedish population. Cost and outcome data were discounted with a 3% annual rate. Sensitivity analyses were performed to test the stability of the base case results. RESULTS: The economic analysis showed that adjuvant treatment with HuIFN-á for stage IIb-III melanoma patients resulted in €8200 higher costs and 2.5 additional QALYs, leading to an incremental cost per QALY gained of €3300 compared to no adjuvant treatment. Including costs of added years of life increased the cost per QALY gained to about €21,100. The results were stable in sensitivity analyses. CONCLUSION: The economic evaluation indicates that adjuvant treatment with HuIFN-á is cost-effective for patients with resected cutaneous malignant melanoma in stage IIb-III.