Prostate cancer is a common malignancy primarily of elderly men, with incidence rates rapidly increasing, owing to the population ageing and the introduction of more sensitive diagnostic procedures. Although the effectiveness of a screening test remains controversial, the decreasing mortality rates, which recently emerged in the USA, may be partly attributable to the changes of patterns of care, thus suggesting a potential effect of preventive measure. The object of this study is to examine time trends in incidence and mortality from prostate cancer in European Union (EU) countries, with particular attention to possible differences between the elderly (65 years old or over) and younger or middle age adults (35-64 years old). EUROCIM, the data base created by the European Network of Cancer Registries, provided the incidence and mortality data for the 12 EU Countries analysed (namely: Finland, Denmark, Scotland, England and Wales, Ireland and The Netherlands in Northern Europe; Austria, Germany and France in Central Europe; Italy, Spain and Portugal in Southern Europe), for the 1978-1994 period. Incidence and mortality time trends, expressed as mean difference per cent (MD%) per year, were estimated by a Poisson log-linear regression model. Higher resolution analyses were also carried out to check differences in time trends by age class within the two groups under study. Upward mortality trends occurred in several countries, excepting Ireland, Austria and Southern Europe, but only for younger and middle aged adults. Rates increased more rapidly in older age groups; a clear north-south gradient appeared both in the elderly and in younger adults; for the elderly, MD% higher than +1.5 for most countries of Northern Europe, MD% around +1 for Central Europe, and MD% less than +1 for Southern Europe were registered, with lower values for younger people. Incidence rates rose across the period considered, almost in all countries both for elderly and for younger and middle age adults, increasing more rapidly in younger age. Incidence trends showed a less clear geographic pattern than for mortality. In the younger group, high MD%, ranging in Northern Europe from +3.2 in Finland and England and Wales to +5.7 in The Netherlands, were observed, while in the South values ranged between +4.2 and +5.0. In Central Europe, very high MD%, ranging between +8.4 in France and +16.6 in Austria, were noted. No significant trends were observed for Denmark, Ireland and Portugal. For the elderly the increase was generally lower and no significant trend was observed in Germany and Portugal. Interaction between age and calendar period in the older group was observed for most of the considered countries. With reference to mortality, the MD% showed a tendency to rise, with increasing age, while no consistent pattern emerged for incidence. The observed incidence trends are probably a consequence of the different times in which the more recent detection methods were introduced in each country, and of the different policies adopted by each health care system towards the elderly. A comparison with the USA data suggests that in the next future a favourable downward mortality trend could be expected also in some EU Countries and, particularly, for younger age groups, even though prostatic cancer in old patients will remain a great burden, which National Health Care Systems will have to face in the next decades.