The aim of this study was to estimate the cost-of-illness associated with completely resected stage IIIB/IIIC melanoma with macroscopic lymph node involvement, overall and by disease phase, in France, Germany and the UK. This retrospective observational study included patients aged older than or equal to 18 years first diagnosed with stage IIIB/IIIC cutaneous melanoma between 1 January 2009 and 31 December 2011. Data were obtained from medical records and a patient survey. Direct costs, indirect costs and patient out-of-pocket expenses were estimated in euros (€) (and British pounds, £) by collecting resource use and multiplying by country-specific unit costs. National annual costs were estimated using national disease prevalence from the European cancer registry and other published data. Forty-nine centres provided data on 558 patients (58.2% aged <65 years, 53.6% stage IIIB disease at diagnosis). The mean follow-up duration was 27 months (France), 26 months (Germany) and 22 months (UK). The mean total direct cost per patient during follow-up was €23 582 in France, €32 058 in Germany and €37 970 (£31 123) in the UK. The largest cost drivers were melanoma drugs [mean €14 004, €21 269, €29 750 (£24 385), respectively] and hospitalization/emergency treatment [mean: €6634, €6950, €3449 (£2827), respectively]. The total mean indirect costs per patient were €129 (France), €4,441 (Germany) and €1712 (£1427) (UK). Estimates for annual national direct cost were €13.1 million (France), €30.2 million (Germany) and €27.8 (£22.8) million (UK). The economic burden of stage IIIB/IIIC melanoma with macroscopic lymph node involvement was substantial in all three countries. Total direct costs were the highest during the period with distant metastasis/terminal illness.