Using individual subject data from 10 case-control studies, comprising over 3000 cases and almost 4000 controls, we have estimated the relative risk of melanoma associated with aspects of complexion, namely, hair, eye and skin colour and freckling in adulthood, and have examined the relationships between these factors and naevus count in terms of melanoma risk. Compared with individuals with black or dark brown hair, the relative risks for developing melanoma in those with light brown, blonde and red hair were 1.49 (95% Cl 1.31, 1.70), 1.84 (95% Cl 1.54, 2.21) and 2.38 (95% Cl 1.90, 2.97), respectively. Individuals with blue eyes had a risk 1.55 (95% Cl 1.35, 1.78) times that for those with brown eyes, or 1. 15 (95% Cl 0.94, 1.40) after adjusting for hair colour and freckling in adulthood. The relative risks associated with hair and eye colour were independent of those for naevus count and skin colour. Light skin colour and high freckle density were also highly significant risk factors, independent of each other and of naevus count and hair and eye colour. The risks associated with these factors, while individually modest, are largely independent, and thus pigmentation characteristics and freckling tendency should be useful in identifying high risk groups to be targeted for prevention. © 1995 Wiley-Liss, Inc.