The age-standardised incidence of prostate cancer varies more than one hundredfold between the areas with the highest and lowest incidences in the world. In certain areas, in particular the Western countries, the incidence has increased rapidly over the last 20 years. There are several environmental and genetic factors which partly explain these variations, although the incidence probably depends most of all on the extent to which small latent tumours are detected. As the clinical significance of small tumours is uncertain, the value of early diagnosis and early aggressive treatment is controversial. Randomised trials addressing this question have been initiated and will hopefully provide more evidence-based data in a decade from now. Small localised tumours are managed by radical surgery or radiation therapy. In elderly men or men unfit for operation or radiation therapy surveillance is often preferred. For advanced or metastatic prostate cancers androgen deprivation has been the mainstay of treatment since the early 1940s. Recently, several new treatment strategies have evolved but have not yet been introduced into clinical routine.