Objective: Mortality rates of anorexia nervosa (AN) are generally assumed to rise with increasingly protracted follow-up periods. Reports are highly variable, with rates ranging between 5 and 20%. A rate of 5.9% resulted from very recent meta-analyses. Causes of death of AN patients ranged from suicide to sudden death. Method: Findings so far published on clinical course, follow-up, outcome, prognosis, mortality, and sudden death in AN cases were systematically analyzed with the view to checking on divergent definitions of mortality rate, crude mortality rate, mortality death rate, and methodological problems of recording which may be causes of variability of data and evaluations. The same variability applied to descriptions of causes of death in AN. While suicide data usually are precise, most of all deaths resulted from inadequately defined complications of eating disorder, and in some cases the cause of death, including sudden death, is reported as unknown. Results: The crude mortality rate due to all causes of death of AN patients was found to be 5.9% by means of linear regression in a meta-analysis. However, no absolute, precise data were given on causes of death, including sudden death in AN. Reference is made to the great variety of somatic alterations as well as to the role played by cardiac arrhythmia and acute circulatory failure in the context of sudden death. Discussion: Any AN death should be fully reported for proper elucidation of the causes. Neuroanatomic, neuropathological, and neurohistological studies should be conducted, primarily into the right brain hemisphere for accurate determination of etiological relationships between cerebral function, brain alterations, and AN. An account is given in this paper of preliminary results obtained from a quantitative-neurohistological investigation of the brain of a female AN patient aged 13.5 years who died a sudden death.