Incidence and mortality of melanoma have increased among men and women in Europe. We analysed the incidence and mortality of cutaneous melanoma (CM) in Northern Ireland. Three thousand eight hundred and thirty-seven incident cases of CM were reported to the Northern Ireland Cancer Registry (NICR) from 1984 to 2006 and 1177 melanoma deaths occurred from 1955 to 2007. Trends were analysed using joinpoint regression and a negative binomial model was fitted to test the linear trends for incidence adjusted for calendar year, age, sex and Breslow thickness. Age-adjusted incidence rates of CM increased significantly in both men and women (estimated annual percent change (EAPC): 4.8% and 2.5%, respectively). The increase was essentially due to thin melanoma (<1mm). In contrast, there was a stabilisation of incidence of thick melanomas (4mm) in men and suggestion of a decrease in incidence of thick melanomas in women (EAPC: -1.5, 95% confidence interval (CI) -3.6;0.6). Mortality rates increased steadily in men over the whole period 1955-2004 (EAPC: 1.8%, 95% CI 1.1;2.5) whereas in women it increased until 1980 and decreased after (EAPC: -1.0%, 95% CI -2.5;0.6). We report for the first time a downward shift in all age mortality after steady increases but for women only. The plausibility of this shift is supported by similar downward trend in thick melanoma incidence in females only. Although there has been an active sun protection programme in Northern Ireland since 1990, the reason for the changes in female mortality which predates the programme remains to be fully understood.