We discuss the assessment of testamentary capacity (ability to execute a valid will) in elderly people. Such assessment should include evaluation of the person's knowledge regarding the purpose of the will, the extent of the property involved, the legal heirs, and how the property is distributed according to the will. Some conditions may invalidate a will, including insane delusions and undue influence; however, the mere presence of severe mental illness, such as schizophrenia or dementia, does not automatically render elderly people incompetent to execute a valid will.