Some recent studies have shown an association between sleep disordered breathing (SDB) and cancer mortality and incidence but no study has focused on a specific type of cancer. The objective of this study was to analyse the relationship between the severity of SDB and factors related to cutaneous malignant melanoma (CMM) aggressiveness.We performed a multicentre observational study in 82 consecutive patients diagnosed with CMM. 56 patients in whom melanoma measurements were available were finally included in the study. Melanoma measurements of aggressiveness included: tumour mitotic rate, Breslow index, presence of ulceration, stage of disease and growth rate of melanoma. A sleep study was performed in all the included patients. Multivariate analyses were used to examine the independent relationship between SDB severity (apnoea-hypopnea index (AHI) and nocturnal oxygen desaturation indexes (ODI3% and ODI4%)) and measures of CMM aggressiveness.60.7% of patients had SDB (AHI ≥5) and 14.3% severe obstructive sleep apnoea (AHI ≥30). In fully adjusted multivariate analyses, AHI (OR 1.08, 95% CI 1.02-1.14), ODI3% (OR 1.08, 95% CI 1.02-1.11) and ODI4% (OR 1.1, 95% CI 1.02-1.2) were independently associated with an increased melanoma growth rate. Furthermore, AHI, ODI4% and ODI3% were significantly correlated with other aggressiveness factors of CMM, such as Breslow index, presence of ulceration and mitotic index.SDB severity markers are associated with some aggressiveness markers of CMM.