The course of untreated localized prostate cancer after 10 years of follow-up is at large unknown. As curative treatment is usually only offered patients with a life expectancy exceeding 10 Years, the expected course of the disease if left untreated is of the utmost interest. This paper aims to describe the outcome for patients who survive for more than 10 years when treated without curative intent. The results indicate that cancer specific mortality in patients with localized prostate cancer increases steadily over time and is approximately 50% after 15 years. This is a much higher figure than in reported series on radical prostatectomy. Even if many deaths occur at an old age, prostate cancer death is shown to be associated with a significant morbidity, need for palliative treatment, hospital care and cost. Preventing prostate cancer death is therefore not only a matter of saving year of life but also to prevent suffering caused by the disease. Modern diagnostic tools, such as prostate specific antigen, seem to detect clinically significant cancers in the vast majority of patients. Over diagnosis seems to be uncommon if diagnostic procedures are restricted to patients with a long life expectancy. Localized prostate cancer is a slow-growing but progressive neoplastic disease. When diagnosed in a man with a longer life expectancy it should be handled as such.