Life expectancy in Spain has more than duplicated during the last 20th Century, and is currently 75 years for men and 83 years for women. Predictions on the evolution of the National and global population anticipate a demographic shock in Spain when individuals older than 65 years eventually make up more than 33.5% of the Spanish population by year 2050. It is known that cancer is directly related with age, and that it is a disease of older people -at least 60% of all cancers are diagnosed in patients older than 65 years. The older people group is the most important group of patients in oncologic practice today. Predictions on the aging of the Spanish population show that cancer in the aging patient and its treatment must be considered a first-line health problem. The diagnosis of cancer is not associated with death in the majority of patients. Sixty percent of cancers are globally cured or chronified. This advanced prognosis has its toll not only in the expectancy of treatment but also in subsequent follow-up and post-treatment adverse effects that can be generated. A greater and better knowledge and understanding of the aging process will allow to identify and select those old patients that can benefit from prevention and treatment options, and more importantly will identify those other patients that are not candidates to treatments with curative intention because of their frail status. Progress in surgery, mainly in minimally invasive surgery, and its application to the field of oncologic surgery allows to forecast that a greater number of aging patients will benefit from treatment with curative intent. Age will not be a barrier for adequate treatment in healthy elderly patients, especially in those with long life expectancy and functional reserves. Fighting this healthcare discrimination is one of the main priorities in the strategy of improved health in the elderly. We present in this study and analyze the foreseen changes in the world s population, particularly in Spain; the association between cancer and age with its peculiar specificities; the general criteria for frailty in older patients, the limitations that aging generate for adjuvant treatments, and the new alternatives of treatment to be used in elderly oncologic patients for the most frequent tumors.